I would say it's subjective, in that one person may think Fallout looks better than Crysis.
Also, some games look better than others in places, only to look much worse when you get to the next level or stage. For instance, when I first ran up Fallout 3 on my desktop, (while still in the vault) I thought "Man, this game looks so OLD!". But then as soon as you venture outside of the vault, the whole game completely changes and it looks amazing.
But I would say I think a couple of the best looking games I've played have been the Gears of War games.
Also, some parts of Fear 2 look spectacular, especially some of the effects they've put into that game.