Bitsync is very good but it is not quite a dropbox clone as it lacks the ability to retrieve the files via web, it does very limited version control, it has a pretty rigid structure of sync'd folders (for instance you can't sync a subfolder of a folder you are already syncing). Some of those functions can be implemented using owncloud but this latter is still bit buggy and requires you to have server space.
It is not as polished as Dropbox yet, but since this is Hacker News one solution would be to have BitTorrent Sync running on a home server then you could just SSH/sFTP to retrieve files. I have a Raspberry Pi running 24/7 on my home broadband with DDNS + BitTorrent Sync on it.
