I used to have a lot of problems with spyware/malware that got past my free anti-virus programs. (I was using Adaware and AVG) I had given up on system resource hogging programs like Norton and McAfee long ago.

I did my research and found Spyware Doctor which is a great anti-virus/spyware/malware program. It removed all the crap that was on my computer and I haven't had a single problem since. It is pretty cheap (comparatively speaking) at up to 3 computers for one low price of $40.00. There is also an annual renewal fee of $40.00. For me it's worth it for the peace of mind it delivers without hogging my system resources and acting like a virus itself.

I also highly recommend a free download called SnoopFree which will detect and block keyboard hook attempts. It works great and I have been surprised at what programs attempt to hook my keyboard. They haven't updated it for Vista yet so for now it is only good for XP users.