Huh, interesting, because that exact problem is one of my key complaints with windows search, while I've never noticed it with spotlight -- and I've been using spotlight daily since Tiger.

Well, that's not quite true, for a few years after spotlight was released it would get slow after a while, so I mainly stuck with Quicksilver. Eventually spotlight got faster, but I never had that particular problem with it, even though I very regularly have that particular problem on Windows.