Yes, as a matter of fact it is. And I LOVE the thought of rating the underrated movies!

What does underrated mean?

The general consensus of how good a movie is is less than it actually is? (e.g.: Legally Blonde is generally dismissed as fluff but it is actually a pretty good movie!)

The number of people who have seen a movie is disproportionately low compared to how well regarded it is by those who have seen it?
(e.g.: A Simple Plan was one of the best movies of the 1990s but only 4,000 people ever saw it)

Just as the AFI list uses actual film-making quality (as much as such a subjective term can be pinned down with the word "actual") AND cultural/industry impact AND commercial success as ranking factors, I think both of those two definitions would be viably used in compiling such a list.

Sight & Sound has been doing an international critics poll every ten years since 1952. The latest list (from 2002), which can be found here, shakes out like this (this is the list, in order, of all movies which received more than four votes):

1. Citizen Kane (Welles)
2. Vertigo (Hitchcock)
3. La Régle du jeu (Renoir)
4. The Godfather and The Godfather Part II (Coppola)
5. Tokyo Story (Ozu)
6. 2001: A Space Odyssey (Kubrick)
7. Battleship Potemkin (Eisenstein)
7. Sunrise (Murnau)
9. 8 1/2 (Fellini)
10. Singin' in the Rain (Kelly, Donen)
11. Seven Samurai (Kurosawa)
11. The Searchers (Ford)
13. Rashomon (Kurosawa)
14. The Passion of Joan of Arc (Dreyer)
15. A bout de souffle (Godard)
15. L'Atalante (Vigo)
15. The General (Keaton)
15. Touch of Evil (Welles)
19. Au hasard Balthazar (Bresson)
19. Jules et Jim (Truffaut)
19. L'avventura (Antonioni)
22. Le Mépris (Godard)
22. Pather Panchali (Ray)
24. La dolce vita (Fellini)
24. M (Lang)
24. The Story of the Late Chrysanthemums (Mizoguchi)
27. Barry Lyndon (Kubrick)
27. Les Enfants du paradis (Carné)
27. Ivan the Terrible (Eisenstein)
27. Man with a Movie Camera (Vertov)
27. Metropolis (Lang)
27. Some Like It Hot (Wilder)
27. Ugetsu Monogatari (Mizoguchi)
27. Wild Strawberries (Bergman)
35. Andrei Roublev (Tarkovsky)
35. The 400 Blows (Truffaut)
35. Fanny and Alexander (Bergman)
35. La Grande Illusion (Renoir)
35. The Magnificent Ambersons (Welles)
35. Modern Times (Chaplin)
35. Psycho (Hitchcock)
35. The Seventh Seal (Bergman)
35. Taxi Driver (Scorsese)
35. The Third Man (Reed)
45. Bicycle Thieves (De Sica)
45. Blade Runner (Scott)
45. City Lights (Chaplin)
45. Greed (von Stroheim)
45. Intolerance (Griffith)
45. Lawrence of Arabia (Lean)
45. Letter from an Unknown Woman (Ophuls)
45. The Man Who Shot Liberty Valance (Ford)
45. Mirror (Tarkovsky)
45. Ordet (Dreyer)
45. Pierrot le fou (Godard)
45. Rio Bravo (Hawks)
45. Sansho Dayu (Mizoguchi)
45. Shoah (Lanzmann)
45. The Travelling Players (Angelopoulos)
45. Two or Three Things I Know about Her (Godard)

Hmmm, I skimmed that, but I sensed a definite trend towards ignorning everything after 1975.

I would think more the latter than the former. And I loved "A Simple Plan."
I'll throw out two favorite underrated (or under radar) movies: "Five Corners," and "Once Around." For a "bigger" picture that I don't think got anywhere near the recognition it deserved, I'll go with "Everybody's All American."

I like this Sight and Sound list! There are a few I haven't seen and probably should.

I love The Magnificent Ambersons.
Is it on DVD yet?

I hear it's coming soon in the US - I have a decent French DVD.

Oooooh!

:)