What Vista applications require internet access?

I put this question here as it really is firewall-generic:

Starting out with a firewall that defaults to blocking all outbound applications, what specific applications in Windows Vista require internet access (particularly, what files / .exe's require it)? I have iexpore.exe set up, but in particular I'm looking for the apps used in Windows Update and Automatic Updates.

I set up wuapp.exe -- So I now know WHAT updates are waiting for me, but can't download them Thanks in advance for the help!