There are a bunch of great new CLR v4-related video interviews up on Channel9.  In particular:

• Jon, Thomas and Dave from my team (CLR diagnostics) discuss the advancements in debugging and profiling APIs in v4
• Simon and I discuss in-process SxS (ability to have multiple CLRs loaded in the same process).  You may have noticed the lack of diagnostics blog entries from me lately - that's because I've mostly been spending my time helping out with this important feature.

There are a bunch of other ones that look good (eg. "Type equivalence" and "No-PIAs" are closely related and an interesting discussion), but I haven't gotten a chance to watch them yet.