Another update. Sorry it's been a while, but apparently I have to do real work at my job from time to time.
I tried looking over policies applied to my system/user and comparing them with another. I also even compared my registry hive against another user's to see if anything stood out. A few curiosities but nothing I looked into from there panned out. I even tried resetting all my caspol configurations to no effect (a shot in the dark).
I ended up moving the location of my desktop (right-click on your desktop folder in your profile and go to the Location tab) to a Desktop2 folder in my profile. Success! I then renamed my old, broken desktop folder and moved my desktop back from Desktop2 to the new Desktop and it still works. Yay.
Sorry to report that I still have no idea what the issue was but, hey, at least it was easily remedied. I did notice one new thing when I compared my new desktop folder's SDDL string against the old one when I included audit information (e.g. get-acl -audit). The old one has a blank SACL (apparently) hanging off at the end of the SDDL (it just stops at S:
). That seems kinda odd, but I'm hardly an expert. Either way, next time I'm in office, I'll try and wipe the SACL on that folder to see if it clears up the issue (which is still very much intact with items placed in that folder) and/or clone the permissions from my new desktop to that one.
Anyway, if that fixes it then I'll post back here. If not, I suppose it will remain a mystery.