WoW:Druid vs. Shaman?

I have finally narrowed my choices to a Shaman or a Druid. But I can not decide which to pick. I like the fact that a Druid can fly and change forms to do different things. But, I also dont know if I can wait until levels 30-40 to be great in combat. On the other hand, a Shaman is great in solo PvE with totems, but I hear is really bad in PvP, whether it be world PvP or arena. Which cl is good for solo, grouping, instances, and PvP? I know a cl is only as good as you make it, but can anyone point me in the right direction? Thank you.