Here is where I stray far from the mainstream ('Norton', 'McAfee', etc.) and the "second tier" products (Panda, F-Protect, etc.) and go for what really works at a terrific price - Grisoft's AVG. I started using 'AVG' when one of my virus data file subscriptions to Norton Anti-Virus ran out. I refused to pay another $40-60 for a product I knew was not as fast or effective as the alternatives. I absolutely, positively refused to give any money to McAfee for a totally inferior product. I had been testing 'AVG' for about a year on one of my servers - their free version 6.x. It worked flawlessly - meaning that a) it performed well and did not hog up a lot of CPU time or memory and b) it scanned quickly and c) found and resolved virus problems. When GriSoft released version 7.x I immediately signed up and paid the $20 they asked for and never looked back. I have recommended 'AVG' to a few friends and people who e-mailed me about their systems, and they are VERY happy I did. One reader tells me her system runs like new since she deleted McAfee and installed AVG.
There is an incredible amount of just plain crap on the Internet, special search add-ons, pop-up this, pop-under that, spy-ware here, ad-ware there, just plain annoyances and security risks. For the past three months I have been removing 'junk' from quite a few of the 800 PCs I've been supporting. I use two tools - Spybot Search and Destroy and BHO Demon. Spybot Search and Destroy scans and finds about 6000 potential spyware and privacy-threatening remnants on your PC. BHO Demon finds all of the little 'bugs' that have attached themselves to Internet Explorer - bugs you will not find otherwise without getting into the Windows Registry. These are must have tools to keep your system clean. Looks for details about these little bugs in my "What the heck..." section.