We're making the move to 64-bit at work, and one of the things that's annoying me the most is all the 32-bit shell extensions that I rely on and didn't realize it.  For example, we use Subversion for source control and use the excellent TortoiseSVN shell extension to work with it from explorer.  Since it's a 32-bit extension, it doesn't show up in the context menu.

There are two workarounds I've found for using these 32-bit extensions.

1. Use the 32-bit explorer.exe in the SysWow64 directory.  You have to have the "Launch folder windows in a separate process" option turned on, otherwise it will just see that explorer is already running and start a new 64-bit window instead of a new 32-bit process.
2. Use 32-bit IE.  There's already a shortcut to it by default in the start menu.  Just fire it up and navigate to the filesystem instead of a web page.  Voila! 32-bit extensions start showing up.  I like this method since I don't have to have a bunch of explorer processes for each window.

There's probably a cleaner way of using the 32-bit explorer, but I haven't figured it out yet.