I'm playing Gears atm and in terms of realistically achievable graphics today, I think it looks far superior to Crysis. Maybe in a year's time (or three!) when I upgrade and replay, that will change. (I played it on medium).
Best game? Hmm... not played even half of the ones on the list but I'd have to say all the ones I have played (Crysis, Orange Box, Bioshock and Gears of War) have not lived up to expectation. Having said that, I'm barely into Gears of War yet, so will reserve judgement.
Best would have to be Bioshock, I think. Great storytelling, though let down by repetitiveness.
Can I just have a mini rant about Orange Box? (tough, I'll do it anyway)... All the parts of Orange Box are good games, but not great games. A lot of people tend to lump them together and consider them as one game, since the package is so cheap. I think people are misleading themselves on that one. Price doesn't make a game great, and although the pakage is great in these pricey days of £30-£50 per game, the actual gaming experience involved in each game is not elevated. A bunch of good games, not one great game.