Yes, I know this isn't a UX quirk, but hear me out:
This feature is so simple, yet so brilliant. I can't believe I never thought of this. Why not have integrated support for online storage services (Like Windows Live SkyDrive) via plugins? (See picture). That way we could easily use the drive just like any other. Other services could make plugins for their online storage services too.
Btw, the credit goes to deviantartnab from deviantart.com for the concept picture. Here's the full picture in context: