After a lot of trying and researching i found that under win 7 on my two machines (x86 and 64) the best protection with least resource usage is
Avast Home (all set on high)
Prevx (with real time protection and high heuristics, 0 conflict with avast)
and Hitman Pro (on demand, cloud scanning with multiple engines).
Cisco hardware firewall, Vista Firewall Control Pro (the version which should be paid is running for more then a month now for free with no pop-ups, go figure)
Web of Trust addon for IE8 with custom security zone, NoScript Firefox, and AVG Linkscanner.
Remote control is turned off and so is unnecessary network sharing and some other services, DEP is turned on for all.
With all that my resource usage is so small it's not even noticable. System is secure and passes all tests with flying colors. I haven't had a single problem with Windows 7 on two different machines since I switched 2 months ago.
I'm a happy surfer