I have a small problem, which I am sure is a common one. But I wouldn't mind a bit of advice.
My party consists of:
me (fighter), Minsc, Keldorn, Jeheira, Aerie, and Nalia...
This works ok, but I find Nalia is a pretty bad theif, and cant advance very far as a mage... I am considering getting either Korgan, or Edwin, or maybe both, but I am Chaotic good, and most of my party is good alignment, this would probably cause some conflicts...
I want to get a good mage, and a better theif, Who should I get?

Jan jansen is both of those things... almost. He is an Illusionist / Theif that is a much better theif than Nalia, though a weaker mage than Edwin. Perhaps you could keep Edwin around and pick up Jan just to hear the contrast in personality.

You can find Jan selling stuff near the park in the Gov't District.

I couldn't agree more more. Jan Jansen is the man for you.

I have a problem along the same lines.
I have a party that currently consists of Myself(archer kit whoo!) minsc, viconia, aerie, nalia (but only till I get imoen) and jaheria (got me a romance goin)

I just recently offed old kraag, and now I have this beautiful carsomyr holy avenger thing. is it worth dumping minsc for? should i dump someone else?

Dump Aerie.
Never found her that useful.
(I made half of the game with a Bard as the only non-cleric spellcaster

/Morninglord of Sweden

'sup sylent
cya at school

see I would, but shes hella usefull. Shes got tons of spells (sucked back a potion of intelligence or two and learned anything I could) and has a kick ass turn undead effect.