I have a larger dropbox account than my primary hard drive. It would be great if dropbox could support virtual links to files outside of it's default location, without those files having to also be in the main dropbox folder. I am aware of shortcuts/aliases on windows/OSX, but those don't solve the problem if my primary drive has limited space.
This is one workaround, but native support through the Dropbox client would be ideal: http://bobmckay.com/software/split-dropbox-across-multiple-drives