Personally I have to agree with suggestions so far, check the following thread for similar.....
http://www.cableforum.co.uk/board/38...-pc-guard.html
I regard PCGuard on a similar footing with Norton (although I understand Norton have been listening to the thousands of complaints and are cleaning up their act), ie its bloatware, system/resource hog that seemingly doesnt do any better a job than free virus protection.
I use clamav with linux
For the family xp desktop Avast, occasional sweep with Spybot (although Windows Defender is supposed to be getting better now for spyware, it was previously Webroot Spysweeper I think, Microsoft snaffled it up and initially made a mess of it), and no firewall (sitting behing two nat routers both with hardware firewalls, so not necessary). Yep I know inbound traffic isnt the only problem so if you dont have 100% confidence in your setup/habits Zone alarm is your friend, whatever firewall you have for outbound traffic though requires a fair bit of study and setting up, even the big name bloatwares dont do everything for you in that respect.
The only other protection I use is an up to date hosts file from mvps.org, which these days is a snap to update using HostsXpert (scroll down the following page to find it)
http://www.mvps.org/winhelp2002/hosts.htm
Stops your machine being linked to bad sites in the first place, full stop.
Also spywareblaster from javacool software is good as an extra preventative measure for both firefox and IE (but make sure you get the right one, there are miss-spelt imitators which are nasty)....
http://www.javacoolsoftware.com/spywareblaster.html
I dont believe there will ever be one piece of software that will ably and un-obtrusively (ie quickly/seemlessly/silently) protect a windows machine, its a constantly and fast evolving landscape which can take over your life just upkeeping it. Virus and spyware and the hybrid combinations which help install each other .... and as for rootkits I dont think anything is capable of protecting from those yet (do some searching and you will find its practically rocket science, I have seen quantum physics theories used in the same paragraphs explaining the workings of some aspects of rootkits), true or not you decide but the claims of bloatware companies are always just to sell the product.
So anyway, just some extra options (when you get totally cheesed off with the bloatware and recurring suggestions to ditch it) which (IMHO) at this time are very good.
Edit: LOL and, forgot to mention the ultimate protection, when it all goes pete tong, the best prevention is format your hard drive and do a clean re-install of everything (trick is staying offline before you are totally setup with protection, and not accepting all the default links and bloatware your machine supplier gave you). But of course, to succesfully do that you need OS installation disks, and a lot of experience with your machine and its driver setup. Good luck