Shadow of the Colossus is one of my favorite PS2 games, and I now have the HD version on PSN as well. I have a few quibbles with horse control and the default button set up, but being able to change said setup was really nice. It took me a long time to get passed the electric eel-type Colossus in that one lake, because I have a pretty intense fear of leviathans in the ocean. If they'd had a Colossus that was actually in the sea, I doubt I would ever have been able to complete the game.
My favorite Colossus to fight is the "horse" whom you have to trick into looking into one of four sits of barrows, then run out another and climb up its back. My least favorite aside from the lake colossus is the s[piny lizard thing that shoots thunderbolts at you.