Windows Home Server
I installed Windows Home Server on an old box here at home yesterday, and I am impressed. This is one well-executed product.
It's basically a Windows 2003 Server, somewhat stripped down, with a server piece that can take a pool of raw storage and turn it into SMB shares that are optionally replicated onto more than one physical drive.
There are two significant client pieces. One is the backup agent, and the other is the Windows Home Server Console, where you administer and monitor the server. The console architecture leverages Remote Desktop, so the admin console actually runs on the server itself, and the client is a specialized Terminal Services client designed to wrap it. The user doesn't really need to know this, but there are some signs that this is what's going on that you can pick up on if you use RDP enough.
I installed the backup agent on a few machines around the house, and it just started backing things up to the server. There was very little configuration involved.
The server by default exposes some special folders for Music, Pictures and Videos, and shares these using the Windows Media Connect protocol that the XBox 360, Windows Media Player, Windows Photo Gallery and the Zune software use, so you can keep your media on your server where it's mirrored and backed up, and still use it where you need it.
The fact that the server has SMB shares that are automatically pooled and mirrored makes for a good backup solution for the Mac as well - just rsync into this folder. Hopefully TimeMachine will be able to backup into this folder as well.
So kudos to the WHS team on a great product.