I use Avast but I HATE their new software updater.
Go to add/remove programs and click uninstall/change on avast.
When it opens choose change and go and remove anything you dont want from it, including the software updater lol
For me I only have 2 scanners installed with avast, file system shield and behavior shield. Everything else is unchecked. I still get the protection and avast doesn't hit my system no where near as much now.
Shane