Okami is amazing and stunning in every way. There really isn't much else to say.
The game's graphics are stunning and unique, and the music is beautiful. It plays and feels just like a painting that's come to life. The story is engaging, and mixes in traditional characters and stories from Japanese legends to form a highly unique game that is just beautiful to play. I was in awe the entire time I was playing it.
The camera is fully controllable, and never awkward, and the fighting mechanics flow well. There's a huge environment to explore, with a wide variety of sidequests (think Zelda). It's a completionist's dream. The rewards for 100% completion are well worth it, with art and soundtracks on the main menu, and the ability to replay the game in 'God-mode', for lack of a better term.
I'll admit it, I neglected my other games to play this through a second time straight away, and I tend to go back and play it again every now and again. It's an amazing game that everyone should own.