if all you want to do is level three dudes without stopping go with shamans they can rez,heal and beat ass. for good trio that can do low instances go with pally and two shaman. I use a druid,pally,3x ele shaman for my main team and they take out everything. as far as doing melee i never wasted time with that. positioning and stuff is way to much of a pain but targeting and hitting one button is easy. unless you are not planning on doing heroics or much endgame instancing with the team by yourself i would definitely stick a pally in there as they are the best tank imo.