Well, I can tell you, I've just finished SoA, and am now on to ToB as a solo sorcerer, and I must say, it's the most fun I've had since I first beat the game.
Soloing gives you the opportunity and forces you, at the same time, to use alternative tactics, as well as giving you a very good sense of accomplishment when you finish the various hard bits.
After this solo, I'm probably gonna try the "New Champion with Mods" Wizard Slayer->Thief that Dundee proposed. I must say that soloing really breathed new life into BGII for me.
