WMP works great as a media server, but it has limits in the type of files it can share.

It can not share or play flac files natively. You can install a patch that allows you to play flac files, but I don't think it's possible to share them with your network.

The xbox 360 is great, but as I mentioned it does not support flac. They did recently add DivX support which is cool for video streaming/sharing.

-David