There is a rule for presenters: every time you put an equation on the board/screen you lose about half the audience. I think that can also apply to presenting on the ins and outs of a network stack. We've got clever with the stack in Vista, and Server 2008, and some of the improvements have been ported to Server 2003. When I explain the details I can feel the boredom from the audience.
We've just posted a study by Tolly Group , and here's the main conclusion.
Just upgrading client PCs to Microsoft’s Windows Vista can yield throughput and time-to-completion improvements of up to 2.5X over Windows XP.
Complete migration of servers to Windows Server 2008 can yield throughput and time-to-completion improvements of up to 3.5X over Windows XP/Windows Server 2003.
The improvements are most pronounced on networks with a lot of bandwidth, but high latency - so I notice the improvement downloading large files from Redmond to the UK.