avast! Home Edition

Among many Anti-Viruses, avast! home edition is one of the freeware available for download.

Although it may not be THE BEST Anti-Virus, it is fairly effective and efficient, good for a normal home user. Most important of all, it's free.

Highly recommended for users that are busy, or lazy(that's me :P) to scan your pc regularly.
It offers On-Access scanning feature, which constantly scans your computer in background, and uses very few memory for it. Unlike some powerful Anit-Viruses, avast! doesn't eat up much space of your harddisc.

Performance:	good
Ease of use:	very good
Feature:	great
Supports:	satisfying
System Requirements:	low

Overall ratings: 9/10

The default GUI of avast!
Looks like a stylish media player. You can change the skin too.

External Links:
Official Website
Download for Windows
Download for Linux
Register here

Reviews:
from wikipedia
from CNET
from TopTenREVIEWS