There are games that seemingly have better textures ( aka. GT5 ), but ill always give the graphics award to Crysis due to the sheer amount of vegetation and as yahtzie puts it, if you have a vegetation fetish, you'll love this game...and I do. Lets see how Killzone 2 does since all those console kiddies have been raving about that.
PS: Crysis Warhead never really looked like much of a graphical improvement imho over the original Crysis