Recently I've been looking into software and solutions to have media streamed to my computers. I have a large number of video, music, and picture files that I would like accessible. This may be different in what you're looking for if you're trying to stream a DVD for instance (but can be fixed by making a video file out of it, of which all I know is that it's possible).
I've found that
XBMC has been my front end of choice. It connects to anything that you have (well, not my TV tuner yet, but I think it's close), and plays anything you have, regardless of your OS, the protocols you need, codecs, etc... Ok, for Windows it's a snap, but and for Linux it's very easy and there are fairly easy instructions to get it working. It has a very clean interface as well. I've been very impressed with it. Some downfalls I've seen, it is looking like it needs some moderate hardware to run smoothly. I've been running it on my EeePC netbook, and I've noticed freeze for 1-3 seconds at a time when changing and selecting options, or loading a music or video file. For a netbook, I'm very happy with it as I'm normally waiting that amount of time anyway for it to respond. It works Wonderfully on my desktop PC as well.
XBMC has just released version 9.04 today, and I'm excited to try it out. Their Beta 1 version was very stable and I was very happy with it. I'd highly recommend it to anyone, or at least give it a try, if they want to stream their media from any where to their PC.