When you use windows update will Avast 6 interfear with it? Should you leave the real time shields on or turn them off?
It will scan the files downloaded, executed etc. But will not interfere(finds a virus) if everything’s fine. Keep the shields on. Absolutely nothing to worry with avast and windows update.
avast does not interfere… it scans.
Let always the shields ON 
windows updates seem to take longer to download than normal. i dont know if this is avast related or a problem with the windows update servers. its definately not my ISP because it used to download them rather fast. I am using Windows 7 Sp1 64 x Avast 6.0.1000
Most recently the Windows servers have been downloading gazillions of IE9 updates.
Just before that their servers were downloading gazillions of W7 SP1 updates.
I always leave all Avast shields on. I never had a problem. And you are correct in that there have been many updates recently no matter what OS you have.