depends really... if you're talking general spyware removal i use the following:
Ad-AwareSE 1.06
SpyBot 1.4
MS Antispyware
HijackThis
(ocassionally SpySweeper)
If you're talking individual removal tools, I currently have 30, (but only use a few... listed below):
CWShredder
Killbox
About:Buster
ADspy
HSRemove
Also, worthy of mention are some other necesities for protection and clean up/fix proceedures:
SpywareBlaster
Hoster
CCleaner
RegScrubXP
IEfix
WinsockFix
LSPfix
Most of these are for experienced users (italics) that KNOW what they're doing with them, (otherwise you could really mess up you're machine).