I thought at first that I’d imagined it, but now I’m positive: Windows 7 sometimes deletes some of my icons off of my desktop when it reboots. Today, there at at least 6 missing: One to my Computer icon, all of the ones to my external drives and my CD drive, and one of my folder shortcuts.
My first thought was some sort of “unused icons” cleanup, but most of these were ones I used yesterday, so that can’t be it. Instead, it’s most likely a bug in the desktop manager or something. So annoying.