If your "samurai" means "chanbara" in general:

1.Okami Yo Rajukitsu o Kire: Fun-Hen, Gekigo-Hen, Doto-Hen (The Last Samurai, 1974) by Misumi Kenji.
2.Porno Jidai-Geki: Bohachi Bushido (1973) by Ishii Teruo.
3.Daibosatsu Toge (Sword of Doom, 1966) by Okamoto Kihachi.
4.Daibosatsu Toge (Satan's Sword, 1960) by Misumi Kenji.
5.Bakumatsu Zankoku Monogatari (Brutal Story at End of the Tokugawa Shogunate, 1964) by Kato Tai.
6.Bakumatsu (The Ambitious: The Restoration of Meiji, 1970) by Ito Daisuke.
7.Shinsengumi Shimatsuki (Legend of the Shinsengumi, 1963) by Misumi Kenji.
8.Goyokiba (Hanzo the Razor, 1972) by Misumi Kenji.
9.Shikake-Nin Baian (Professional Killer Baian, 1981) by Furuhata Yasuo.
10.Kagegari (Shadow Hunters, 1972) by Masuda Toshio.
11.Sasaki Kojiro (Kojiro, 1967) by Inagaki Hiroshi.
12.Aoi Shingo (Shingo, 1959) by Matsuda Sadatsugu.
13.Kiba Okaminosuke (Samurai Wolf, 1966) by Gosha Hideo.
14.Kogarashi Monjiro (Cold Wind Monjiro, 1972) by Nakajima Sadao.
15.Kaette Kita Kogarashi Monjiro (Return of Cold Wind Monjiro, 1993) by Ichikawa Kon.
16.Kozure Okami (Lone Wold and Cub, 1972) by Misumi Kenji.
17.Shinobi no Mono (Ninja: Band of Assassins, 1962) by Yamamoto Satsuo.
18.Mekura no Oichi (Crimson Bat, the Blind Swordswoman, 1969) by Matsuda Sadatsugu.
19.Miyamoto Musashi (Sword of Fury, 1973) by Kato Tai.
20.Momotaro Samurai (1957) by Misumi Kenji.
21.Nemuri Kyoshiro (Sleepy Eyes of Death, 1963) by Tanaka Tokuzo.
22.Shirikurae Magoichi (The Magoichi Saga, 1969) by Misumi Kenji.
23.Hangyakuji (The Conspirator, 1961) by Ito Daisuke.
24.Onmitsu Kenshi (The Searching Swordsman, 1964) by Funatoko Sadao.
25.Onna Sazen (Woman Sazen, 1968) by Yasuda Kimiyoshi.
26.Tange Sazen (One-Armed, One-Eyed Swordsman, 1966) by Gosha Hideo.
27.Zato Ichi (The Blind Swordsman, 1962) by Misumi Kenji.
28.Zato Ichi (1989) by Katsu Shintaro.
...
I don't know which ones have been edited in DVD...

Nice list calros, but I have to add a bunch that you didn't list:

Sanjuro
Three Outlaw Samurai
Kill
Hidden Fortress
The Blindswordsman vs. The One Armed Swordsman
Samurai Rebellion
Shugun's Samurai
Yojimbo
Samurai Assassin
Red Lion
Also When The Last Sword is Drawn, a recently made samurai flick.

You are right, Mr. Magic. I wanted to add about 50 more, but Mr. Ghost asked only 25...

It's very difficult choose only 25...!

...
29.Akado Suzunosuke (1957) by Kato Bin.
________First of a 9-film series. Combines swordplay and fantasy.
30.Iga no Suigetsu (Ambush At Iga Pass, 1958) by Watanabe Kunio.
________The best of all the films about master swordsman Araki Mataemon.
31.Araki Mataemon: Ketto Kagiya no Tsuji (Vendetta of Samurai, 1952) by Mori Kazuo.
________The most famous film about Araki (here played by Mifune Toshiro).
32.Benten Kozo (The Gay Masquerade, 1958) by Ito Daisuke.
________The best version of Thief Benten story.
33.Chushingura (The Loyal 47 Ronin, 1958-59) by Watanabe Kunio.
________The first version in color about that famous story (and also the longest, 2 Parts of about 170' each). More oriented to drama.
34.Chushingura Gaiden: Yotsuya Kaidan (Crest of Betrayal, 1994) by Fukasaku Kinji.
________Combines 2 stories: 47 Ronin and Yotsuya Ghost Story. Very odd fantastic film. Too odd...
35.Daibosatsu Toge (Souls in the Moonlight, 1957-59) by Uchida Tomu.
________Filmed in 3 parts. Not as good as the Misumi & Okamoto versions...
36.Dokuganryu Masamune (Hawk of the North, 1959) by Kono Juichi.
________First version in color based in the famous dramatic novel by Ishizaka Yojiro.
37.Fukuro no Shiro (Owl's Castle, 1999) by Shinoda Masahiro.
________Semi-realistic adaptation of the novel of Ninja specialist Shiba Ryotaro.
36.Ninja Hicho: Fukuro no Shiro (Castle of Owls, 1963) by Kudo Eiichi.
________First version of Shiba's novel, and also the best.
37.Gokuaku Bozu (The Wicked Priest, 1968) by Saito Buichi.
________First of a series of 5 films, starring an odd priest.

Hatamoto Taikutsu Otoko
38.Hatamoto Taikutsu Otoko (Bored Hatamoto Samurai, the Idle Vassal, 1959) by Sasaki Yasushi.
________One of the best in the series (1930-63), all starred Ichikawa Utaemon. Based on the novel by Sasaki Mitsuzo.
39.Isshin Tasuke (1967) by Yamashita Kosaku.
________The last film about the japanese "Robin Hood".
40.Kaiketsu Kurosukin (The Black-Hooded Man, 1960) by Kono Juichi.
________First of the 8-film series. Based on the novel by Takagaki Hitomi. More oriented to intrigue.
41.Kenan Jonan (Trouble With Swords, Trouble With Women, 1951) by Kato Tai.
________First version with sound of Yoshikawa ("Miyamoto Musashi") Eiji's novel.
42.Kozure Okami: Sono Chisaki Te Ni (Lone Wolf and Cub, Final Conflict: Handful of Dust, 1993) by Inoue Akira.
________More realistic, but no as good, than the Misumi version (1972). From the comic by Koike and Kojima.
43.Kunisada Chuji (Gambling Samurai, 1960) by Taniguchi Senkichi.
________The last version of the best story of "matatabi" (gambling wanderers) sub-genre.
44.Kunoichi Ninpo: Hyakka Majigarimi (Female Ninja Magic: 100 Trampled Flowers, 1974) by Sone Chusei.
________The most famous version of Women Ninja novels specialist Yamada Futaro. Combines "ninpo" and "pinku" genres.
45.Shin Kurama Tengu (New Kurama Tengu, 1965) by Yasuda Kimiyoshi.
________First of the 2 films, based on the character created by Osaragi Jiro. It's a new version of the old film series (1927-56).
46.Kurama Tengu (The Black-Hooded Avenger, 1956) by Uchide Kokichi.
________Not as good as the former, it's a series of 4-films, firstly in B/W and later in color and CinemaScope.
47.Onmitsu Hicho: Maboroshi-Jo (Spy's Secret Scroll: Phantom Castle, 1956) by Hagiwara Ryu.
________More oriented to fantasy. Based on the Takagaki Hitomi novel.
48.Shinken Shobu (Death Match: Swords of Death, 1971) by Uchida Tomu.
________Epilogue of the "Miyamoto Musashi" film series (1961-65).
49.Hiken (Secret Sword: Young Swordsman, 1963) by Inagaki Hiroshi.
________Very interesting plot: Combines fictional characters with historic ones (Miyamoto Musashi). From the novel by Gomi Kosuke.
50.Momotaro Samurai (Free-Lance Samurai, 1963) by Inoue Akira.
________Not as good as Misumi version. Based on the Yamate Kiichiro novel, it's an adult version of a children short story.

Tomorrow, more.

51.Abarenbo Mori no Ishimatsu (Ishimatsu of the Forest, 1959) by Saeki Kozo.
________Light version of the spin-off of the "Shimizu Jirocho" story. 2 Parts.
52.Hengen Murasaki Zukin (The Black Hood's Transformation, 1963) by Kudo Eiichi.
________The last version of the old story by Susukita Rokuhei. Adapted by Kato Tai.
53.Nemuri Kyoshiro (1956) by Hidaka Shigeaki.
________First version of the novel by Shibata Renzaburo. 3 Parts. Slightly inferior to the Misumi version.
54.Nihiki No Yojinbo (Two Bodyguards, 1968) by Misumi Kenji.
________From the novel by Hasegawa Shin. Very hard to find.
55.Iga Ninpo-Cho (Ninja Wars: Black Magic Wars, 1982) by Saito Mitsumasa.
________Maybe too fantastic view of ninja genre, remake of a film series (1963-65). Novel by Yamada Futaro.
56.Kogan no Waka-Musha: Oda Nobunaga (Oda Nobunaga, the Rosy-Cheeked Young Warrior, 1955) by Kono Juichi.
________Biopic about the famous general, from the novel by Yamaoka Sohachi. First part, youth of Oda.
57.Fuunji Oda Nobunaga (Oda Nobunaga The Man, 1959) by Kono Juichi.
________2nd Part. Nakamura Kinnosuke plays Oda in the 2 movies.
58.Waka-Ki Hi no Nobunaga (Days of Young Nobunaga, 1959) by Mori Kazuo.
________New version about the youth of Oda, but now based in the novel by Osaragi Jiro. As good as the later.
59.Oku Maruhi Monogatari (The Shogun And His Mistresses, 1967) by Nakajima Sadao.
________2 Parts. More oriented to "pinku".
60.Iro Goyomi Oku Hiwa (Secret Story of the Shogun's Harem, 1971) by Hayashi Isao.
________Ditto.
61.Roningai (Jobless Samurai, 1990) by Kurogi Kazuo.
________Last version of the novel by Yamagami Itaro. Very interesting movie, supervised by Makino Masahiro.
62.Roningai (Street of Masterless Samurai, 1957) by Makino Masahiro.
________2nd. version of the novel, not so good as the 90s film. Makino directed the silent version, too (1928-29).
63.Ninjutsu Sarutobi Sasuke (Ninja Spy, 1976) by Yamane Shigeyuki.
________The last version of that fantastic story.
64.Ibun Sarutobi Sasuke (Samurai Spy, 1965) by Shinoda Masahiro.
________From the novel by Nakata Koji. Typical B/W Widescreen ninja film of the 60s.
65.Satomi Hakkenden (Legend of the Eight Samurai, 1984) by Fukasaku Kinji.
________From the fantastic novel by Takizawa Bakin. There are a lot of version of that story, some in pure SF POW.
66.Seki no Yattape (Samurai and Orphan, 1959) by Kato Bin.
________Its title says it all. From the novel by Hasegawa Shin.
67.Jirocho Sangokushi (Jirocho of Three Provinces, 1963) by Makino Masahiro.
________From the novel by Murakami Genzo, this is the last version of the historic character Jirocho of Shimizu.
68.Shinobi no Shu (A Band of Ninja: Last Iga Spy, Mission Iron Castle, 1970) by Mori Kazuo.
________Spin-off of the "Shinobi no Mono" series (1962-66).
69.Shinsengumi (Band of Assassins, Band of Samurai, 1969) by Sawashima Tadashi.
________New version of the Shinsengumi, produced and starred Mifune Toshiro.
70.Shinsengumi (2000) by Ichikawa Kon.
________Puppet animation. Nakamura Atsuo dubbed Kondo Isamu.
71.Gohatto (Taboo, 1999) by Oshima Nagisa.
________"Yaoi" (Homo) version of the Shinsengumi story. Starring "Beat" Kitano. Very good twist.

Shura Yuki-Hime
72.Shura Yuki-Hime (Lady Snowblood, 1973) by Fujita Toshiya.
________The first, and the best, version of "Broken Oath", based in the comic by Koike and Kamimura.
73.Hakuchi (Samurai Vendetta: Chronicle of Pale Cherry Blossoms, 1959) by Mori Kazuo.
________Based on the novel by Gomi Kosuke, is the last version of the famous story "Takeda-no-Baba".
74.Hiken Yaburi (Broken Swords, 1969) by Ikehiro Kazuo.
________Combines the stories of Nakayama Yasubei and Tange Sazen. From the novel by Gomi Kosuke, adapted by Ito Daisuke.
75.Tange Sazen (1963) by Uchikawa Seiichiro.
________The funniest retelling of the famous Ooka's Trial story, with Tanba Tetsuro playing two roles.
76.Yaji Kita (Yaji And Kita on the Road, 1958) by Sawashima Tadashi.
________2 Parts. It's the last version of their adventures.

I think I forget several films more...

Let's get this thread going again.

One great sword-film not mentioned so far is

HARAKIRI (1962)

with Japan's Lawrence Olivier - Tatsuya Nakadai.
Basically more a pyshcological thriller,
but with plenty of sword-slashing along the way.

Twilight Samurai?
www.imdb.com/title/tt0351817/

There are tons of Jidai Geki films to watch too (most include Samurai ), but here are some Chambara (Chanbara) films not mentioned:

Am I the only fan of Samurai Fiction? I'm glad Emperor mentioned Twilight Samurai which is a very good film.

I don't think Sword of the Beast is mentioned either - http://www.imdb.com/title/tt0200768/combined Which is good, not as good as Kill (Kiru) or Yojimbo (almost everything Kurosawa does is awesome) but better than the Hanzo series.

Beat Takashi's Zatoichi version is pretty good too (better than Shintaro's last Zatoichi, but not as good as the earlier Zatoichi's) so I would not put it as a top 25 pick.

lady snowblood is a classic.

Watched Hideo Gosha's GOYOKIN last night - definitely one of the better Samurai films I've seen. KILL! is another great one.