Windows Vista, Home Premium, SP 1
ZoneAlarm Extreme Security 8.0.400.20

I've been reading some posts about using Windows Defender with ZA, and I'm confused!

Some posts say using WD with ZA is fine
Other posts say using WD with ZA can cause problems
Other posts say that WD is not very good at what it does anyway

So I was wondering if the safest thing to do might be to uninstall Windows Defender before installing ZoneAlarm Extreme Security?

Is WD just anti-spyware, or does it do more than that?
Won't ZA be providing that function anyway?

Thanks for any help!

Operating System:Windows Vista Home Premium
Software Version:8.0
Product Name:ZoneAlarm Extreme Security