I use spybot and install the sd helper but I don't consider it a resident shield, teatimer is too dangerous to leave activated from my past experience with it. The immunize feature with spybot I do regularly update and then do occasional scans. How many you can leave active depends upon the stability of your system and whether you can tolerate the loss in performance. It's best to not even have two fullfledged antivirus programs installed, but anti malware's seem a little safer. Experiment with spysweeper's shield.
If I had a quad core and 2 gigs of ram I would experiment more.
Too many programs running is almost like having a system crippled with malware. It's a little easier to fix tho.
Edited by DaChew, 16 February 2008 - 09:10 PM.