Managed code at the 64 bit world

One of the great new features of Whidbey is the ability to run some of your CURRENT managed applications *natively* on 64bit machines. Some interesting thoughts on this came up in a recent post and it got me talking with the folks working on the 64bit CLR. For geeky folks that like to know exactly how the CLR works, I think there are some fascinating things to find out here.

-Pitfalls of PInvoke when moving across platforms

-Differences when debugging the 64bit CLR

-Discussion of running managed code in the WOW64

-GACs, 32bit/64bit/portable

-Performance

-etc

What interests you from this list? What other topics would you find useful?