Another reason to make new characters for CotAB is that your previous characters from PoR will be too high level, making the game too easy.
Also, it can be helpful (but not necessary) to have at least one female character for CotAB.
My preferred party for CotAB: 5x Elf F/M, 1x Human Cleric
However, this party would be unsuitable to transfer to SotSB.
Yes, I love F/M :)!!
cbarchuk: Thanks guys for the suggestions. Are single class characters pretty weak in this game compared to dual or multi class?
It's often a balance, especially with MU, because multiclass will reach the more powerful spells a bit slower and have fewer of them available.
In CotAB you start hitting level caps which make multiclass a bit more unsuitable too (most notably the Cleric), and by SotSB the multiclass characters will be more underpowered.
I never dual-class (just because I find it too cheesy for me personally :D), so I can't comment on that.