Both of those are good and if I remember correctly BitDefender was easier on system resources. Kapersky is also very good but a bear on sr’s. I got tired of the yearly subscription scam and I just use the CA I got free with Roadrunner and the CA firewall. I have used CA and Firefox for 4 years and have never had a virus.
I've been using Firefox since ver 1.5 and I preach it to my friends. Any DOS crap / Windoze systems running XP/VISTA has to have at least 2 Gb of RAM as not to crawl. Currently I am in the process of a new build and then demote an old Dell on the network for a front end firewall / AV to run in ubuntu before the wireless router. Linux will pretty much be blind to a hacker and the method I will use to deploy it. Everything behind that, except to the most skilled hacker (US goobermint in particular), will be pretty much invisible. Still that doesn't 100% remove the risks associated with downloaded trojans, malware, viruses.
.Corporate made the decision to go MS years ago...I was forced then to learn Windoze, so I use it at home to interface with work....I like it when I get the opportunity to play with MAC's and their apps.