Some awesome videos for comparison:

3) Metal Gear Solid 4 gameplay (for good quality download from PSN):
http://www.youtube.com/watch?v=tV3CMtD8rBo

2) Killzone 2 - bullet impact / death sequences (BTW, IMO Crysis death sequences are pretty sucky in comparison, download from PSN for good quality):
http://www.youtube.com/watch?v=QEO_DWiEhlI

1) Uncharted 2 - ordinary walkthrough gameplay (IMO best looking game ever):
http://www.youtube.com/watch?v=5-Sh55YEDLk

All 3 games look great, especially on a HDTV in full quality.

I'm going to have to go with MGS4 for it's perfect gameplay-cinematic integration. Killzone 2 has impressive graphics but they are too grey. Uncharted 2 has very good graphics with many different environments and colors. I guess you can just say I prefer MGS4 and therefore I prefer its graphics haha.

1. MGS4
2. Uncharted 2
3. Killzone 2

that video is kinda terrible ,but they did the ragdolls , AI and enemy voices perfectly in this game. sometimes killing them makes me sad. especially when i killed one and the other screams "YOUR GOING TO PAY!" in a sad/angry and attempts to take revenge on you.

Uncharted 2 wins. MSG4 to me had great character animations but left a lot to be desired from the background, plys both MSG4 and KZ2 are very dark games. Uncharted 2 has bright colors and manages to do the lighting properly on all of them Also, the In Game graphics don't drop off from the cinema graphics all that much.

^^MGS4 isn't dark....are you sure it's MGS4 you've played?

Killzone2 in lighting and scale. Lighting because of the obvious. Scale because it's huge and there's so much more going on compared to Uncharted or MGS4. I'd say MGS4 beats Uncharted in scale aswel.

Textures, it's close but I say Uncharted 2 over killzone 2.

Everything else, Uncharted 2 no question.

Overall, Killzone2 is more impressive on the tech side of things but Uncharted 2 is just drop dead gorgeous when it comes to art style, vivid colors, lots of foliage and extremely detailed environments.

Such a hard choice... I've always had the following opinions:

Killzone 2 is the FPS Graphics King

Uncharted 2 is the Action/Adventure Graphics King

Metal Gear Solid 4 is the Stealth Graphics King (yeah MGS4 is Action/Adventure but... the graphics are sooo good you just can't ignore it!)

But if I had to choose out of the three... Uncharted 2 takes my vote. Just watching Shambala alone AMAZED me immensely!

Uncharted 2 looks the best. Likely due to style.
Metal Gear Solid just looks great, but pretty typical.
Killzone, looks bland.

Having played all 3 extensively, My vote goes to Uncharted 2.

The game is just beautiful. The environments, character model, and lighting are absolutely perfect.

KZ2 is a close second though.

Killzone 2