If you guys are familiar with Live Mesh but no need of remote connection what soever, this might catch your attention. Dropbox is basically an online storage service--2GB for now--which has cross-platform client running natively on Windows, Mac, and surprisingly Linux also.
After couple days of trying it, it just works. There is no fancy feature or customized location yet. But it gets job done with less memory than Mesh, of course. It works flawlessly so far on my several PC and Mac. Since it's only BETA, you will be expected to test its flow, report and suggest to the developer. If you guys would like to try, I have 10 invites available. =)