So I upgraded to Vista as soon as it was released, and needed a compatible Antivirus program.  Knowing how wrong these things can go (I'm the family computer guy), I did a fair amount of research.  In the end, I went with BitDefender, because the limited reviews I saw had it ranked pretty high, and the price was reasonable.  Oh how I wish I had gone into the future to read PCWorld's review.  They VERY MISTAKENLY still ranked it "Very Good", but they at least mentioned the painful performance drop.  To that though, I would add that I have no end of trouble with getting Windows Update to work w/ the antivirus on, so I effectively have to manage things manually.

I'm going to switch to a free alternative until I see whether BitDefender is going to update this piece of junk or not.