"The best, no question."5.0 starson by FJR_Pilot
Pros: The software is unobtrusive (though you can make it annoy you if you like) and doesn't hog up my system resources and slow down my computer.
Things I also like:
-Trend Micro Vault
Cons: It doesn't give me the ability to punch spammers in the face over standard TCP/IP.
Summary: After becoming increasingly frustrated with security solutions from those two "big names", I did some research and tried Trend Micro, and have never looked back! Do yourself a favor. Stop wasting your time with those other guys and get Trend Micro Titanium. And for those of you who like those free anti-virus programs: You get what you pay for.