The plot, characters, and settings were all Bio's work. Black Isle did stuff like voice talent and whatnot.
Thanks for clearing that up. Was one of those things that I'd read had been cleared up, but never actually saw what was done by whom. Even read that Feargus commented on the issue, but, typically, never saw that post, either.

Regardless, their shift away from that sort of world exploration is what's making me most leery of Dragon Age right now. Loved BG1 for that "complete" feeling, liked what there was of it in BG2, found it lacking in ToB, and was downright disappointed with it in NWN, so much so that it really affected my enjoyment of the game as a whole. Even so, though, I could still fill in the numerous blanks from what I knew of the Forgotten Realms from other sources. A brand new world with brand new creatures that I'm not allowed to explore aside from a few set paths or closed off areas is something that's likely to irritate me more than anything else. It just doesn't appeal to me. Could still be fun to play, but it's certainly not my first choice of game.
I'm hoping they'll move back to a more BG1-ish world-design philosophy, since I've heard that they're still sticking with areas and loading screens, but I'd be surprised if it happened as well. That's not saying that I don't think a game can't overcome that with enough depth in other areas, but just that it's what I'm hoping for.
Volourn: Can't recall where I've ever said that Bioware's only contribution to the BG series was the engine, or that they didn't deserve the lion's share of the credit for it, but I suppose it's not outside the realm of possibility that others have. You're certainly free to lump me in with those nameless entities, I guess, even if it's wildly inaccurate to do so. All I really know (well, knew, now) was that there are two logos in the intros to the games, and that Bio did the vast majority of the work. Precisely what the breakdown was between the two companies... just wasn't sure.