Exactly the same as with TRON 2.0.

Anachronox would be a wonderfull live action movie.
Gabriel Knight 3 - Blood of the Sacred Blood of the Damned probably could be an awesome trhiller.

Star Control 2...
The epic journey through hilarious space.
Obviously the movie shouldn't take itself too seriously. Probably better as a decent anime or CGi film then live action. That way you could have all the original voice actors contribute.

Though this is a little ahead of schedule:
I always wanted a movie AND game version of Ender's game.
I think i heard that both are in the works. I think EG wuld make an awesome movie.. and while the real world stuff probably wouldn't work as a game, i always wanted an RTS that controlled like the game in Ender's Game... fast, fluid, about timing, feints and picking weak spots.
Homeworld meets Darwinia maybe...
--
The thing about most games is that the GAMEPLAY is mostly gruntwork. The gameplay generally revolves around repeating the same few actions a lot until a cutscene apears and actually advances the plot. Hence the only parts of games and movies that are often compatible are the cutscenes.
Also, most gaming settings and characters tend to be generic stereotypes. This is intentional, as gamers usually (MGS apart) don't want to sit through lots of cutscenes and exposition building up characters. So a stereotypical character can be introduced and understood much more efficiently by the game designers.
But this means most games don't translate well into movies, where there needs to be more depth and more originality. Characters from fighting games, for example, tend to look stupid in real life. Games like Doom, Halo, Half Life, etc.. are all essentially based on the generic Aliens idea. Those kind of settings and characters work well in a game... heck, Doom didn't even need cutscenes.. we instinctively knew who the player was, as we'd encountered them so often before in fiction.
Even the most generic or average blockbuster movie (eg: Stealth, Blade, Riddick) tends to have way more character depth, interaction and development than most of the deeper video games. Different needs, standards and expectations. Depth in games comes in terms of gameplay mechanics.
System shock 2 is one of my all time favorite games, has great atmosphere, a memorable villain, and great depth and mechanics... but nothing in it (with the possible exception of the villain) would translate well into a movie... and even if it was done, and done well, it'd just be a generic scifi movie.
--
Interstate 76 directed by Quentin Tarantino...

If they were patched up to be less ridiculous, Kojima's Snatcher and MGS games would make great movies. Kojima aspires to be in the movie biz, and it shows in his games. I'd prefer a Snatcher movie though, cause I'm pretty nostalgic for another movie like Blade Runner.

I think The Journeyman Project would make a good movie. Point and click adventure games are already structured like movies.

TF2...The Movie.
Just kidding.

Hot Fuzz the Videogame....