We just completed the .NET Framework 3.5 update to the Commonly Used Types and Namespaces poster.
Here's a link to the PDF if you want to grab it now and be the first on your block to get it on your wall. We'll be using it at a variety of places, if you think it would be a cool thing to have at a Microsoft event then please go suggest it to some Microsoft employee that you know.
Let me point out the little additive circles diagram at the bottom right. We've found that this is a great way to explain the additive version releases of the .NET Framework 2.0 – 3.0 – 3.5. The primary reason for updating the .NET Framework this additive way instead of the side-by-side nature of .NET Framework 1.1 – 2.0 is to make it easier for customers to upgrade their apps. Here's that diagram again.
Update: I posted an XPS version which can print over multiple pages.