I wish BitTorrent Sync had an option to sync encrypted data with relatively "untrusted" nodes, so you could throw it up on a VPS or whatever without worrying too much about the how secure the server is.
Kind of like tarsnap or Tahoe-LAFS, but auto-syncing, etc like Dropbox.
The first open source project to give me Dropbox-like ease of use/functionality with strong encryption will win my support.