Tversity

If you have a XBOX 360 hooked to the interenet, you really need to get Tversity.  I wanted to listen to internet radio while playing games, and this program allowed that and so much more.  I can put in audio/video RSS feeds and listen or watch pretty much any video I can find through my television.  It also allows you to play mp3s from your computer, so you don't have to waste space on your hard drive.  In addition, you can also use it to view photos from your computer and even import them as themes for your background.

I found the video viewer to be Tversity's biggest feature.  It will convert videos on the fly to be viewable on your 360.  I had downloaded a conversion program, but a movie-length video took hours to convert on my PC.  With Tversity, I found that it converted in better quality and I didn't have to wait to view the video.  I strongly urge anybody who would like to use other types of media on the TV to use Tversity.

Some content that I use:
The easiest way for me to set up an internet radio station is with a .pls file.  It seems to work better than adding it through the Tversity itself.  All you have to do is set it to view the folder you save the file to as a an audio source.  You can find most any type of station on Shoutcast.

I also found that Yahoo pipes are helpful for video feeds.  These can be used to combine multiple sources into a single feed or to find feeds that fit certain criteria.  You can also browse previously made pipes if you don't want to mess with setting up your own.  It has quite a few built in as well, such as many G4 and Youtube feeds.