So. You have been using dropbox for some time to make sure all your files are synced between different systems. Perhaps you have shared folders with collaborators and this is how you work together on documents. It has become part of your workflow.
But, there are things that bother you. First, you don't have ownership over where the data is stored. You're not paranoid, but you wonder if trusting all your precious data to an unknown location in the cloud is the best thing. Second, you really cannot afford to pay for more storage, but if would be sooo useful if you could just put everything in the cloud and be done with it, never having to decide whether something needs to go into Dropbox or not.
Enter Sparkleshare. It works on Linux, Mac, and Window 7/Vista (sorry, no XP). It is open source. It is free. And you can store the data in your own system. And it uses git, major geek cred there. That also means you can use sparkleshare to always have the latest snapshots on github etc on your local drive.
The following steps are not too difficult to follow, but it is definitely not as easy as Dropbox.
1. Preparation. As my linux box is running Ubuntu Lucid, I had to upgrade GIT by subscribing to this repository
2. Install sparkeshare, either by subscribing to this repository or installing the client from the website
3. Setup your own data store
4. ?
5. Profit!
Downsides
1. As it uses GIT on the backend, it is not very good at dealing with large binary files. I haven't found any issues yet, but that is what google tells me
2. As it uses GIT on the backend, forget about putting a GIT repository in a sparkleshare folder
3.No iphone/android/Webos clients. Although you may run a web frontend to the GIT repository so you can get to the files that way too.