Killzone 2, mainly for it's superior lighting, animation, and particle effects.  Not to mention I just love the Helghasts' eyes, lol.

Also, Killzone's textures look great in some areas (like the ground in the shots below).  They're probably just still polishing them up in certain areas.  Hell, just look at shots from last year's E3 and you'll see how horrible the textures were then.

(click for hidef)

And some shots to show off the lighting:

And some gifs:

I say gears of killzone. It's pretty obvious...stupid fanboys

^ That.

Even so, I wont make a full judgment on this until we know some resolutions, and until we have seen more levels of Killzone 2! I want to see the KZ2 engine work its magic in a forest, a GREEN forest :D

In my sleepiness, I was comparing Gears 2 and Resistance 2. I gotta go look at some Killzone 2 footage.

Hell i know.Ask when they have come!

Though crudely worded, he makes a valid point :)

KZ2 looks better then gears of war 1.5

based on the pictures and vids in this thread, i would say that Gears takes the crown, the game is just better from an artistic viewpoint for me. But until i have both games running on my hdtv, the case is far from closed.

^^ What he said!

PS: I love that gray pallet, makes it seem more official and EPIC!! ^_^

 PS3 no doubt wins the graphics war, but the gameplay I have to give to Gears.