The releases just keep coming... today it's Network Monitor (NetMon) 3.0. NetMon is a much needed upgrade over the version included with Windows, and even the 'enhanced' version that has shipped with Microsoft Systems Management Server (SMS) for quite some time. The final version number is 3.0.372 and weighs in at 2.5MB. Head on over to Connect and grab your copy - or wait for it to show up on the regular downloads site soon. And, yes - it works on Vista RTM ;)
Here's a screen shot of NetMon 3.0 using a capture filter (shows DNS queries only).
UPDATE: It looks like the NetMon team has decided to keep 3.0 on Connect instead of moving it to the normal download site. Therefore, you'll need to grab a Windows LiveID (i.e. Passport) and head on over to http://connect.microsoft.com. Once logged in, look for the 'Available Programs' link on the left and you should find Network Monitor 3.0. All applications are accepted, so don't sweat it. The official launch announcement from the NetMon team can be found here.
UPDATE 2: Network Monitor 3 was re-released on 12/20 to address an issue with Vista. If you are running NetMon 3 on Vista, be sure to get the newest version (03.00.0372.0001) before April, 2007. Otherwise the application will not function correctly due to a driver expiration issue. Again - this only affects Vista users.