For vista, i have only been using IE.
On one laptop, it is using the IE pro addon.
So far, I dont have much problems with pop ups nor have i been
hit by malware, spyware since about 2 years ago.
It depends on your usage and what kind of sites you surf.
For eg: Those Game ranking top 100s do pop up lots of websites
and direct you to unknown webpages.
TO newcomer: For IE, turn the Protected mode on. Set the
different kinds of secuirty mode. I set mine to med-high.
You can do so by clicking on options, Internet options then go
to the security tab.