If I were you I'd go for Avast! Home.
I was an AVG Free user for a long time, but recently, I made the move to Avast! Home 4.6.
See why: http://www.x64bit.net/site/board/index.php...amp;hl=
Avast Home Edition 4.6
Avast Home Edition 4.6 is free and sports a slick media-player style interface, but its performance scores were bottom-of-the-barrel. Rather than adopting the standard console window used by the other antivirus products, Avast's looks like an oddly shaped orb, which you can customize with colorful skins.
If you want a paid thing, based on the reviews I've seen, these are the best Win7 compatible AVs:
Comodo Internet Security
Kaspersky Lab's latest antivirus software protects you from malicious software of any kind. Also included in the top-notch Kaspersky Anti-Virus 2010 is a virtual keyboard to protect you from password stealing programs, as well as new Kaspersky URL Advisor to warn you from bogus sites so that you can surf worry-free. Its intelligent virus scanning adapts its speed depending on the free computing resources, and ensure your IM and email communication are free of infections. Kaspersky Anti-Virus 2010 costs $59.95 for up to three PC's.For 20 $ more (base price) you can get the ultimate real-time protection Kaspersky Internet Security 2010 which extends Kaspersky 's Anti-Virus 2010 with parental control, application sand-boxing ("Kaspersky Safe Run"), Auto-Run Disable and much more.
Read more: http://www.brighthub.com/computing/smb-sec...4#ixzz0gB7h5r7x
Comodo AntiVirus is now part of Comodo Internet Security suite, which is still free and includes the award winning firewall. Please find the full Bright Hub review of Comodo Internet Security here and note that there is also a Pro edition which extends the antivirus and antispyware with Wi-Fi Security and 24/7 Live Security Expert support for example.
Read more: http://www.brighthub.com/computing/smb-sec...2#ixzz0gB6FkicC
ESET NOD32 Antivirus version 4 protects you from malware including viruses, spyware and Trojans for example. The software, for instance, includes self defense mechanisms, system tools, gamer mode and watches SSL-encrypted communication channels like HTTPS in real-time.
Read more: http://www.brighthub.com/computing/smb-sec...2#ixzz0gB6Zz0Ld
MSE Micrsoft Security Essentials