That's it, really. It's not a ticket to misbehave.
That's what Virtualbox is for. ^_^
Seriously, though, I personally use Microsoft Security Essentials now. Avira was pretty but I got tired of the nagging, especially while I was gaming. If you're not a gamer, it's another option, though MSSE does seem to have a lighter footprint.
I also personally recommend avoiding AVG, as I've had it crap itself (not even because of any viruses!) and take the whole system down. Twice. On two different machines.