Paper CameraThe most fun I've had with a camera in ages, all for a mere $2!
PrintBotThe only full CUPS printing software I've found thus far. Auto-detected my printers and profiles (over wifi), includes all of the needed drivers (2800+ printers), and just plain works easily. The free version is limited to a single printer (at a time), and no more than 3 photos/PDFs monthly; the paid version has no such limits.
Bluetooth Smart PrintingWow.. this app installs itself as a file-sharing destination in
Gallery and other apps. When selected, it pops up a menu of Bluetooth devices, including my BT-enabled HP printer, and simply works without any configuration whatsoever. C00L!