Right on about AVG new version 8.
For years, up until a couple of months ago I gave out AVG to every customer. Then they moved to version 8 and it's philosophy that your system resources are theirs to use.
While still not as bad as Norton or Macafee, they will not listen to knowledgeable people on their user forums.
In the last month or so I have had at least two jobs where AVG 8 has been the main cause of trouble. One was to do with a conflict with Vista SP1.
The problem is it is trying to be a jack of all trades, has become more bloated and makes non-standard adjustments to the system (like winsock).
On many pristine systems it will work fine, but any complications (or a service pack)and like Norton/Mac it compounds the problems. They will soon have to introduce a forcible remover utility like those also, because it won't always uninstall.
My current recommendations are for free antivirus, Avira Antivir. Leaner and better detection than AVG. There is an easy way to fix the one downside, a popup on update, just google it.
For spyware I recommend the free Spybot Search and Destroy 1.4 (google it), but NOT the current version. When installing untick everything except a desktop icon and start menu entry. Do not use helpers or protectors, just run weekly or even monthly. The more recent 1.5 and 1.6 nag you with system prompts if you leave helpers turned on and if you turn them off it freezes sometimes in a scan. AdAware is OK in addition. Avoid SpywareDoctor at all costs it can grind systems to a halt and is not effective. Also, any software that shows you a million problems and demands money to fix them is a fake. I regularly get customers who have paid up.
Lastly if you have a router you don't need another firewall if you are a bit careful, but you have the adequate built in Windows one anyway. The bigger risk with stand alone firewalls for ordinary users is to disallow an unknown program only to have problems later and correcting it requires hunting through menus for unknown names. I have had many jobs where the firewall is the main problem.