I've been using SugarSync for a few months now and love it. I have a computer at home that I do a lot of work on, the Acer netbook for teaching EMS classes at different locations and doing work on the fly, and my computer at school. It was always a pain to keep these computers and the files in sync, but SugarSync has fixed that problem.
I have the "Magic Folder" on each computer and SugarSync automatically keeps them all in sync. That means that I can work on the files on my home computer and it will automatically upload the new or modified file to SugarSync's servers and then when I turn on one of the other computers, SugarSync will automatically download and sync the new or modified file onto that computer. I can also access, edit, and save any file through the SugarSync web site on any computer.
I have yet to need to use more than the 2GB free account, but I'm thinking of upgrading to the 30GB account ($49.99 for the year, or $4.99 per month) and keeping more files accessible.
Try it out. I found it to be easy to use and a great resource. I will be sharing it with my students also, so that they can access their files at school so that they don't have to keep bringing in flash drives.