What do you all think I'd get the most bang for my buck with?
Sk/Bard/Wiz/Mage/2x cleric merc
Sk/Bard/Wiz/Sham/2x wizard merc
I want to run 6 characters but my OCD won't let me be happy unless I do everything on them (epics, clickies, evolving items). 4 seems like a happy medium.
There are a ton of options - most of it depends on what your goals and expectations are. for doing current TBL group content (missions, etc) mercs are not going to give you as much mileage as they may have done in past years, but it isn't the end of the world, you will just be limited. Good news is - once you have a solid foundation it isn't too hard to add in another toon and get them caught up to your main crew.
Healer mercs are notoriously pisspoor for current content and I would strongly encourage you to consider adding in real healer (like your second group)
since you're running a bard - i recommend going towards more of a melee oriented group, but they can compliment casters too
some very popular group makeups using SKs since you have that for your tank
SK/Ench/Clr/Mage/Wiz/Wiz (or any combo of mage/wiz and another mage/wiz or ranger/druid/bst
SK/Bard/Shm 3 melee (rogues, zerkers, beasties etc)
SK/Clr/Bard and 3 melee as above
I personally rock War/Clr/Bard/Zerk/Zerk/Bst - not everyone's cup of tea, but the 2 berzerkers with
@ChatWithThisName mq2berzerker plugin do crazy dps, and the beastlord gives some utility and rings it's own fun to the group. Could easily swap in a SK instead, but I enjoy the warrior just fine. Shm could also work, but TBL has a steep entry for heals
My strongest advice is start with something you enjoy.
Happiness < Min-Maxing until Min-Maxing = Happiness
Best wishes!