Edit: Linked wrong page for Hybrid spec, will fix it laterThis section has been empty for far too long. So I have decided to make a post regarding druid spec - which I have alot of experience in. (around 2000 gold spent in total on respec since level 60)
RestorationThis is the spec I have most experience with as I have played it the longest. There is two type of restoration specs you can have here.
The soloing restoVimax SpaniaThis spec allows for you to do perfect healing with the exception of subtlety (threat reduction) which you SHOULD have once you progress into SSC and beyond. for kara, gruul/maggy you wont generate enough threat to overaggro unless you spam the hell out of regrowth in which case your playing wrong. It also gives you points in balance, for defensive capability (Natures grasp) (Control of nature), and an additional offensive spell (Insect swarm) because we all know how difficult it is to solo as a resto druid... lets face it, its not easy.
The raider resto
full resto.. what more can I say, if you choose this spec dont expect to be able to solo easily - this is a raid only spec.
Hybrid
Many people underestimate the power of the hybrid druid. Saying that without end talents its useless. not true, not true at all.
For raiding, hybrid druids are much more versatile. (This is excluding feral druids, because they have one set gear... they DPS or they tank, they arent efficient at healing or spell DPS)
However... Hybrids are not the best spec for raiding, although they are perfect for soloing and very versatile in raiding you should consider speccing into one particular build.
The balance / resto solo versatile spec
34/0/27
http://www.worldofwarcraft.com/info/classes/druid/talents.html?01430201000000000000000000000000000000000050053301531522531051#none
This is a perfect, perfect solo build for a druid. As you can see you have dreamstate (mana equal to 10% of int, regenned eveyr 5 sec while casting) lunar guidance 3/3. and intensity 3/3. As you may notice in the resto tree there is not alot of focus on HoT's (lack of imp regrowth and only 2/3 of imp rejuv) this is because, as not a full healer you will not have tree of life. and without tree of life your HoT spells will be inefficient and will only be used in sticky situations where you may need a little bit of hp/s on target till you can get a healing touch off. And in the balance tree you can see that we have most of the spell damage talents and the offensive insect swarm and of course moonkin form.
Feral druid
I hope that maybe daehauq or Akhtar will post something here. I'm not too experienced with feral, never really like the spec that much.
However if I had to choose a spec that focused on tanking, and not *so* much on PVP/DPS I would choose this one:
http://www.worldofwarcraft.com/info/classes/druid/talents.html?00000000000000000000055323013232010533125105203001000000000000
Furor, Natural shapeshifter and omen of clarity is a MUST for feral druids, simply put. Other then that as I said I hope the other druids will contribute more to the feral side of things =)