I'd suggest watching the prices and getting a Seagate FreeAgent Dockstar next time they are below $30 (http://www.seagate.com/www/en-us/pro...gent_dockstar/
still has them for $40 if you don't want to wait) for those thinking of going pogoplug.
Allows 3 regular USB drives and 1 mini-USB. Runs the pogoplug and can be "hacked" to do many other things including WRT.
Certainly a great alternative to dropbox, plus you control it more.