I’ve been a balance druid, with some resto leanings, since day one. Leveled that way the entire time however it’s widely accepted that the Feral tree is a more efficient and faster build for grinding out xp. You don’t have mana to be concerned about. You’re not going to take as much damage when running around in bear form. You’ve got the stealth thing going on with cat. You’re much less of a brand-new-meat-sack running around in a t-shirt wiggling your fingers at wolves and spiders.
TenTonHammer has a great leveling guide starting out at level 10 (where Bear comes into the picture) up into the 30′s. They cover a few talent build variations, get into some low level Battle Ground stuff and more. Pretty specific and detailed and free! Take a look at TenTonHammer.com and their low level feral druid leveling guide.