I haven't finished it, but I really like Shadow of the Collosus. In fact I was pretty blown away by it. I just haven't had a lot of time to play it. It did take a little bit for me to get into it, but then it just clicked. There's something pretty incredible about the game. Something very unique and original about it. I love the atmosphere and the gameplay and it does get more challenging and fun as it goes. You're making me want to make the time to get back to it.
I have God of War 2 but only played it for, literally, like 2 minutes. I only tested it to make sure it worked. Seemed OK, I guess. I'm thinking it may not really be my cup of tea, but I'll give it some time when I get to it eventually.
Otherwise the main thing I play on PS2 is still DDR. Lately I'm playing DDR X, which I think is the best US release to date, aside from the awful announcer. I always turn the announcers off anyway, so not a big deal. Great DDR game if you like DDR, so pick it up if you haven't already. Cheap too!