File synchronisation

If anyone mentions Dropbox to me one more time, I will scream. I'm sure it's a wonderful solution, but I have deep misgivings about handing my data over to someone I don't trust. Besides, my synchronisation needs are not that complicated. Here are my high-level requirements: Two way synchronisation between multiple clients and a central server. Automatic syncs - no requirement for manual triggering. Graceful handling of network outages, suspends, etc....