If dealing with a 4-5 man zerg, prot pala and healer. You may not be able to take out the EFC if they run off leaving you with 3-4 people, but there's been times where I just go solo hammer time on a badly geared/played horde zerg.
If it's just 1-2 feral is great. It can keep up with everything and one shot healer FC's sometimes. 1.6k fero bite followed by rake/moonfire and possibly 5 point rip ticks tend to destroy druids/preists/shamans, although sometimes I've had trouble with hpals due to armor.