I have started using Dropbox to share files between my numerous workstations that are spread across labs, work, and home.  I previously have used FolderShare (did not like) and am currently using SkyDrive (which is way too manual and clunky to be useful).  So far, I’m really digging Dropbox and its integration with Windows Explorer.  Very slick!  It also has Mac and Linux clients, and judging from the screencasts, it appears that the integration is just as smooth on those operating systems as it is on Windows.

Shameless Plug: If you want to try it out, please use this link.  That will give me (and you) 250 MB of additional space.