I. Love. This. Game.
I can play it for hours, I never tire of the wide expanse of land you can explore, and riding Argo (and though I am a HUGE Legend of Zelda fan, riding Argo in this game is more realistic and fun! I still love riding Epona, though!). The battles with the colossi themselves is amazing, the graphics are fantastic and with the choice of music I can literally get lost in this game. Even fighting them multiple times doesn't bore me, I look forward to it!
My favorite boss may have to be Phalanx, can't remember which number he was but I think it was 13..? Very hard to pick from, though, cause they're all so fun (and creepy) to fight against XD
Now I wish I had it! But we had to get rid of the PS2 awhile back, and we lost the game while we were moving ._.