Less important than which AV you get is that you spend the time to learn how to use it, and commit yourself to updating it regularly and doing a scan routine. Many people here like AVG because it is free, it is a good choice.
I have used Trend Micro PC-Cillin myself within the last month, and found it to be effective and unobtrusive. It comes with both AV and firewall for $49.95.
Triple6, what problems did you have with it that you can't recommend it?
The AV I currently use is
eTrust EZ Armor by Computer Associates. I get it free courtesy of Roadrunner, but it is priced at $49.95. It has AV, firewall and antispam features. I have been very happy with it, just the other day it caught two trojans that an online RPG gamesite tried to download onto my computer.