I know it sounds as bad as it really is...
As far as I have quite much to do with IT specialists and Admins I can tell even from my experience that most antivirs are rather useless. I mean that they
1) can identify ONLY what they know from their database;
2) heuristic-like features are but non-standard packer-checkers; don't make big hopes here;
3) posing any AV as a front-line cure-it-all makes laugh not only profi, but even average users and children;
4) there's only some 50/50 guarantee to 'cure', not 100% (or even >90%)
. . .
The main drawback is they search re
actively - when the PC is either infected or already got some malware which user can run.
As far as pro
active protection (HIPS) makes it much more efficient and takes less CPU time and thus eliminates most possible software conflicts. I think this is the best way atm:
if it cannot run then it cannot cause damage
Unfortunately, standard HIPS (Comodo+, ThreatFire etc) take a bit of time and require some knowledge and patience to learn the patterns and approve the rules for softwares/processes allowed/denied actions.
The only solution asking almost no question while working and protecting the PC at the moment is paid GesWall PF v3 (beta yet) by Softsphere. Technically speaking it's just a HIPS + a sandbox (virtual isolated environment) + a firewall. It not but an unproved AD: almost a hundred people I know checked and tested it thoroughly. Using GW *properly* one just need to sweep garbage periodically (delete inactive malwares via any updated on-demand virscanner) - they remain harmless and untrusted.
If you still prefer 'standard' solutions then it would be wise to consider only AVs with networking control, HIPS and virtualization.
As for me, on one PC I use free Comodo Internet Security and on two others I use a free ThreatFire and a router (instead of a firewall). As usually it did require some tuning though. Anyway, preventions is always better and more efficient then curing. Mind backups) Hope it helps.