Ad-AwareSpyBotI use those 2 as my main scan and
a-squared (a²) Free edition found, like, 100 stuff(mostly trojans and stuff to re-DL the trojans after I deleted them) the other two didn't/ couldn't clean.
Oh, and
Spyware Doctor also found a lot of stuff the first two didn't, but right after my scan my mainpage turned into about: blank, but I think it got rid of it, not made me get it. And get
Spyware Blaster after you get rid of the viruses to keep them from coming back.