ok After playing a couple of times, and talking to each new NPC, I think I've found a balanced party. :)

Elf mage/thief (protection spells + thief)
Minsc (tank)
Jaheira (good spells, tank, romance)
Anomen (cleric spells, tank)
Edwin (mage) if he fights anyone then Tashi (mage)or Haer'Dalis, I think he'll do nicely :)
Korgan (tank)

does this sound good to you? If i'm already in a 'relationship' with Jaheira will Tashia do anything?

pretty good
just make sure you get yourself some nice elven chain :D

That's a pretty well balanced party: 4 tanks! (wow, I only ever carry 2), 2 healers, 2 mages. Pretty good, make sure your thief skills are sufficient. Concentrate on open locks, locate traps and set traps.
Possibility of an alignment prolem there. Try to keep reputation to beteen 8-12

Not a very balance party. Korgan, the axe-laden, ale-swilling badass doesn't go well with all the goody goodies you've got. Edwin is another evil guy and he and Minsc will kill each other eventually.

This is what I'd do...

Keldorn as the leader
You, a Fighter/Mage as the tank and backup spell flinger
Minsc as your generic evil butt-kicker
Jahiera as your romance interest. She's also a wicked good healer and tank
Anomen as your offensive cleric
Yoshimo/Imoen.

You could change your PC to a Thief/Mage and take Nalia instead of Imoen. That way you wouldn't have to rush off to Spellhold.

Pretty good party. I love mage/thieves. I played one through BG1 and imported him into BG2, he was awesome. I also enjoyed the fact that your main character was doing all the scouting, traps, lock and magic so he was being used all the time.

I would get rid of Edwin as he causes trouble with Minsc. I personally would take Haer'D as my second mage (watch the flames on this one). The beauty about Bards is the level at which they can cast a lot of the low-medium level spells like MM and CO (awesome). I you don't want Haer'D then take Nalia as she is the next best mage to Edwin.

I agree on Haer'D, a lot of people don't give him the credit he deserves. With the right equipment he can be very powerful. Though I think Imoen makes a better mage than Nalia, but until you get her back Nalia could work.