well it's a tough one. I've been a PS2 owner since 2000. and here are a few of my choices:

Metal Gear Solid 3

http://ps2media.ign.com/ps2/image/article/651/651312/metal-gear-solid-3-subsistence-20050915065118995.jpg" border="0">

Silent Hill 3

Zone of The Enders: The 2nd Runner

http://ps2media.ign.com/ps2/image/zoe2_031003_01_640w.jpg" border="0">

I know there are more, these are just examples.

you know one? post it up.

Shadow of the Colossus

I dont know how to embed pictures and screenshots, but my vote goes to Black

1.Shadow of the colossus
2.Silent Hill 3
3.God of War 2
4.Gran Turismo 4

That's extremely easy:

GT4 

@naznatips

Actually that is a pic and definition of 2D sprites at its finest on the PS2 :)

Definitely ZOE 2 with MGS 3 as second in my personal experiences.

Shadow of the Colossus is much better looking in screen shots than in motion. I really wanted to play through the game but couldn't because the frame rate gave me headaches. I'm not flaming by any means. I was very excited to play the game, but stopped trying after I had to stop playing on 3 different occasions due to headaches after 20 minutes or less of play.

 Edit: Gran Turismo 4 was also pretty stunning to look at. It might even edge out MGS 3 for second place. If not, it's close.

@ ecurbj, you got that right.  Odin Sphere, am I correct?