I have same issue but when developping, or making a general task.
I simply can't stand up, till I have finished the task totally or partially or are super super tired.

I am addicted to what I do cos I am serious guy.

So for games: any game I start, I can arrive fast to the end, but as to make it (not finished yet) I don't finish it same day

adventure with nice story games are the best (last game played : uncharted 2)

For me the best game as a realistic one is Arma2, Arma2 Operation Arrowhead
Sad, cuz I bought Arma2 to play online and I cant even join any servers cuz it always kick me, theres too much custom addons for this game that makes so much confuse. But offline game is great especially with custom 3D editor that makes so much fun
Second one was Frontlines, I played online much on that game, great graphics and gameplay, this game was worth the moneys, and the last GTA IV, nice game, gfx, effects, online hmm too much kids and cheaters to play normally =/

im can play forever in one game: tetris
if to be serious. the last game in which im played few hours in a row was freelancer few years ago
ps ultra you still play in freelancer?

Ah man, shame you did M.E. 2 first. Story is very nice, and you'll notice alot of elements / characters that are from the first one which are back. In M.E. 1 you have a lot more options for weapons and armor upgrades etc.

What i notice with a shitload of games lately that get a part 2 or part 3 that they remove almost all options just to make it more noob friendly it seems, to attract a bigger crowd perhaps?

Back on topic, Starcraft 2 single player campaign. Big fan of starcraft, have the first one plus extension, have read all the books aswell. Ingame movies == awesome, story = awesome but a bit short.

For me it was Half life 2. Then episode 1 and 2 (though these were too short). Now awaiting episode 3.

Also Crysis and warhead were fun. (like a modern farcry 1)