I currently use a copy of Crashplan Home installed on a linux VPS, and have each of my Mac and Windows workstaions backup for free (well, still pay VPS fees). I use crashplan in this fashion because I do some IT consulting for some charities, and would cost them a fortune to plan for crahplan's cloud storage.
Crashplan has been a great backup solution -- The server/client can be installed on mac/linux/windows, and the client is a total set-it-and-forget-it program where I am never promted by users about issues or being nagged about updates.
However, in this setup I cannot centrally view all files to be restored (you have to login through each computer), the crossplatformness is done using java and a little slow on older PCs, and finally using this this called "Home Edition" seems unprofessional (even for charity work).
So i guess my question is: What backup servers would you recommend to be installed on a linux VPS, and would have a nice client for windows and hopefully mac?
Thanks all.