For years I employed a conventional backup methodology to backup my personal server to my home server: monthly full backups, weekly and daily incrementals to save space.
A few months ago, my home internet provider (Vidéotron vitiated the quality of their service: from unlimited monthly usage, they slammed a 100 gigabyte limit in our face.
This led me on the divine quest.. “How to quit byte-drinking in 30 days”. I kind of failed and ultimately went for a commercial link, but still have found a marvelous piece of software… Dirvish.
I wish I had made that discovery years ago!
Each night my full backup takes less bandwidth (and time) than a daily incremental previously took (thanks to rsync).
The full tree of what I backup can be accessed like any other file on my drive and takes less space than the previous backups did (thanks to hardlinks)!
Restoring a file doesn't require hours of untarring to find what I'm looking for.. simply cd, copy/scp, and enjoy (or use the included locate-like system to find things first).
For those using a Mac with Leopard, it's very similar to Time Machine.