Apparently there was an interview with Phil Harrison, and he claimed the Killzone PS3 game will look as good, if not better in some cases, than the E3 trailer.
Possible? Probably. Guerilla did a good job of pushing everything out of the PS2 (though framerate would suffer at times...).
Like everyone has mentioned, it's a launch game. The graphics aren't going to be amazing, especially with how difficult it is to program for. I have heard it's still a great game, and the AI/amount of things on screen at once is impressive.
I read a recent article about Halo 3 in EGM (they played multiplayer). They said it looked just a bit better than Halo 2, but the graphics will be much better at launch. Graphically, is the game ready? Pretty much, it just won't wow anyone. If it had been a launch title, I doubt it would look much better than Halo 2.
I'm sure if Resistance had an extra year, no one would complain about graphics.
By the way, I totally won a free PS3 today at the Indiana State Youth Convention . They have to buy it though and mail it to us...sad.