Shamelessly Pimping VLC

VLC (or VideoLan Client) is what I use for pretty much all my transcoding work.

Input methods:
File (all major formats), Disc (Just about any kind), Network (UDP/RTP, UDP/RTP Multicast, HTTP/FTP/MMS, and RTSP), or DirectShow

Output methods:
Well, take a look...
http://www.mustangmods.com/ims/u/2199/5792/78860.jpg

All these options are interchangeable too, so you could be transcoding, playing locally, and broadcasting to your network all at the same time. It also opens up other possibilities, such as using your computer to broadcast a DVD to all the other PCs on your LAN at the same time, or saving live web broadcasts to your computer for viewing later.

You can get it at http://www.videolan.org/vlc/