Running 3 rets, 1 enh sham and feral druid here. As a fresh 80 with 4kGS across the board and 4 or 5 pieces of PvP gear (gotta love honour from PvP levelling) I was able to go straight into heroics and start collecting emblems. Now at 5k GS across the board I do not need to heal other than occasionally for boss fights on ICC 5man or ToC heroics.

I can't recommend the druid highly enough as a tank. I have run a pally and DK tank before who are both now >5.5k GS and the druid feels more durable than the DK and has been much faster and easier to gear up than the pally. Unlike the other tanks, PvP gear is perfect and in some cases BiS for druid tanks so if you do WG quests weekly, 10 x arena matches weekly and the odd BG on weekends, you will have a 45k UBH 32k AR 50% dodge tank in a week or two.

Cheers