Also remember the power of using a
non-Admin user account, which is quite practical on Vista, far easier than it was on WinXP. And if your version of Vista is Ultimate or Business, you can top that with a
Software Restriction Policy too.
For preventing spyware, if you use one or both of these countermeasures, and keep people off your Admin account, keep your system patched, use antivirus software, and exercise a healthy level of risk avoidance (don't download & install junk you don't really know is legit, or that you do know is
not legit), I don't think there'd be much to gain from running an antispyware app on top of it all.
Anyone see a scenario where a non-Admin account, optionally backed by a disallowed SRP, fully patched, with antivirus, not being used in a stupid fashion, gets pwned because it didn't have SpySweeper in addition to all the rest?
/ 2 cents