Sk, shaman, bard and 3 mages is my core group and worked always very well for me. A very solid group able to handle any content.
3 mages is great to use alliance as well. Despite using water-pet it's helpful to use taunt on all pets always. This will cause the mob to swap target almost after any melee-round. The shaman with his hots and hot-similar group-heals will have no problems to keep all alive and even an undergeared sk can start to puller tank. I added the sk as the last char to the team, first just as puller, than followed as puller tank as gear and aa got on par. Now he can tank almost all content with his 2hander, as still often one of the pets catch a round of melee. That way he delivers very nice DPS, despite being the tank.
For content where multiple unmezzable mobs can be expected I have a hotbutton dedicating 1 magepet per add. So upto 4 unmezzable mobs can easily be handled without any trouble.
In the meantime on the bards account I growed an enchanter, a cleric and lately a bst. The enchanter I used, when ToV was new, to fight the eastern waste hero, where I had trouble to control the unregulary arriving adds. Those noe the Sk can easy tank all until the brd controls them.
The cleric I needed for the raid-trash, the Shaman alone was not able to keep the still growing sk alive.
The beast is still on its way to grow up. I am wondering if, once he's sufficient aa'd, he is able to increase the overall group-DPS over the possibilities if the bard.
Resumee: Sk, shm, bard and 3 mages for my feeling is a group with an more than decent average DPS, great to farm any stuff you need and reach max aa with ease. For mezzable mobs your bard does an excellent job, for camps with unmezzable mobs you have sufficient offtanks. For content which you deem still too hard for the team, you can fd-pull and still get the things done.