Ted, I edited your post as you gave away the endgame secret of ToB - in GokuZool's post where he's *asking* about what ToB is like, having obviously never played it. I know you put a spoiler alert on your post and probably didn't mean it, but come on dude, use some commonsense.
The answer to your question was no, btw. ToB is the end of the road as far as the BG saga and Infinity Engine is concerned. Neverwinter Nights is just around the corner though - an almost infinite number of adventures.