For example, if I click
Edit page -> Edit in SharePoint Designer from within my SharePoint site, I'm always presented with a dialog prompting me to download Designer. I already have Designer installed.
Seems like it should a.) launch it for me, or b.) at least stop prompting me to download it.
UPDATE: Turns out this stemmed back to the 64-bit IE compatibility issue that was causing me grief here: How do I enable "Open in Explorer"?