Personaly, I liek the Zoras because I loved swimming around as Zora Link in MM. One of my favourite parts in that game which I'd love to see again (no, TP's wasn't the same). I like the design from OoT/MM the best, although TP's did look pretty good as well. And of course my fav Zora would have to be Mikau.
I'd have to go with the Dekus on this one. They were the most comical, (and in my opinion the coolest looking), race. I liked the fact that they really had no allegiance with a faction, and could be found pretty much in any random crevasse of Hyrule.