But, if you want to know I'm a big fan of two completely different AV's
One has a huge detection rate, but slows your computer down: KAV
The other is much leaner, but detection gets added later and they are not very good at spyware (yet). It makes up a bit for that by using very good heuristics: NOD32
I think I would add a resident AntiTorojan to that last one if I used that AV: BoClean
Please do have a look at my site about removing and preventing spyware.
You will find some other tips there and some links where you will find more information.
P.S. Please do not decide to install both of those AV's resident.