@Seth~: Well, the Kamigawa Block was very interesting to play with. The Japanese-esque design of the Block was another big reason. I myself had a red/white Bushido deck, which did okay. It had the only card in it (at least, that I know of) that could remove all creatures on the field from the game, Final Judgment. The Arcane spells were really fun to mess around with too.
I agree with Aaronock though, they could've made more Arcane spells. Some of them would actually be very interesting in today's Type II decks. Cycling is getting reprinted too much IMO. Flashback would be okay, but I'd prefer if they reprinted (or made new ones) Arcane spells.