A few months ago, I had an entry that showed how to easily get to 32-bit explorer land within 64-bit WindowsXP using Internet Explorer to navigate the file system.  This makes it possible to use 32-bit shell extensions.  In Vista (and possible the IE7 beta on XP), this behavior appears to have changed.  Navigating to the file system simply opens up a new explorer window in the current explorer process rather than loading it within the IE frame.  This is the only gripe I have so far on Vista, and it's probably an IE change, and probably by design.  I'm sure this was changed to reduce the surface area for possible phishing schemes I can think of, but it sure is annoying.

I've seen some possible workarounds on TweakVista and elsewhere, but none that I found satisfactory (I don't want to run the 32-bit explorer as my shell).  So, I may see about throwing together a little app that can host a 32-bit explorer process so I can use my shell extensions like TortioseSVN.