Well, I suppose that's true, but I fold on my computer (folding@home, check it out, people), so I leave it on 24/7 and tell it to update at round 6 in the morning. I can guarantee I won't be using the computer then

. Even during an update, though, it's far less boggy than when Norton loads up...And Norton requires a restart as well. Which drove me absolutely bonkers.

The easiest solution then would be to set your update time to sometime in the middle of the afternoon/evening/when you know it'll already be on. Problem solved

.
I too have also heard good things about Avast!.