i wouldn't touch avg personally.... my uncle is a techie and he swears by it, so it must be decent. i prefer Avast, it's impressed me so far. i haven't had windows 7 long but it works well with it so far. and for the past 3 years i've used them.
The interface is nice and clean, and usually easy to use (except for a few skins), virus database seems to update almost every day, so if they aren't doing their job, they sure are doing a good job of making it look like it.