My druid is lvl 53 and I've been straight balance since about lvl 15. I can crank out pretty good DRS (usually right behind the rogue or mage in groups) and also solo with relatively no problem. With a couple +healing items, I can also easily heal instances. (I have only done through BRD, so i don't know about higher lvl instances). I also PVP. So, balance is great versatility. You can do pretty much anything, and that really helps you get into groups (dps or heal), and gives you a lot of choices of how to play. Feral would probably be better if you're going for a specific experience, but if you vary your play style a lot, I'd say go balance.