Dropbox is very useful. I use 3 computers (one home laptop, one work laptop, one work desktop) and installed Dropbox on each of them. The beauty of Dropbox is that it works even from behind a corporate proxy since it takes the settings from IE. Here is how I am using it:
PhraseExpress: I installed PhraseExpress on all my 3 computers and set the PhraseExpress data file to that in the Dropbox. So no matter which computer I add a phrase in, the same phrases are available everywhere everytime. So essentially I am getting the functionality of network edition of PhraseExpress w/ just its free version and Dropbox.
RoboForm: I have moved the RoboForm's passcards to a folder in Dropbox and all my sites' login and password info is available on all the 3 machines.
Portable Applications: I also use few portable s/w. I just place them in Dropbox on any computer and they get auto replicated on the other 2 systems. I plan to uninstall some installed programs like IrfanView, Notepad++ and get their USB versions and put them in my Dropbox.