My suggestion:
Hands down, the Safest antivirus is your brain! Download only files you have a 99% certainty to be safe, from sources you trust.
I use no AV and scan maybe every 4 months, never a thing besides generic keygens and other false+'s.
Failing that, if you're tired of KIS, go ESET Nod32 or BitDefender. For truly beast protection go G-Data (uses 3 AV engines, bitdefenders, kaspersky and someone else if i remeber right)
Other than that, i install Clamwin AV on friends PC's, very lightweight on resources, no background processes if you choose, and is "scan on demand" meaning scan your comp every once in a while, otherwise scan only files you're suspicious of
Last but not least, my favorite online scanners, what i use personally if im suspicious of something i've downloaded:
Code:
http://virusscan.jotti.org/en[/URL]
[URL]http://virustotal.com[/URL]
Best of luck!