Dont think these are mentioned yet, but i work on several computers during the day (work computer, laptop, another desktop, etc) and wanted an easy way to synchronize all my folders. What I did was carry a USB key, and installed Windows SyncToy on all the computers.
http://www.microsoft.com/downloads/details.aspx?familyid=c26efa36-98e0-4ee9-a7c5-98d0592d8c52&displaylang=en
So I plug in the USB key, run SyncToy and start the sync task.
Another thing I use is Cobian backup, which is self explanatory. Have an external hard drive, run Cobian and make an exact copy of your current Windows files and folders. So if ever the worse happens to your computer, you can always restore your files onto a new hard drive, and return to working as if nothing happened.
http://www.educ.umu.se/~cobian/cobianbackup.htm