@Ayumi: I've posted a thread on the Apple forums, just to see what people will say. If nothing works, I'll give it a go. I'd be less annoyed to know I'm not the only one bogged down with this problem.
@kag: Thanks. Those threads don't quite hit the nail on the head, because my iTunes does more than just mess with my taskbar - it crashes completely. But at least I've posted about my problem there now. Hopefully someone can help.