PC to PS3 streaming, what's my best option?

With Windows XP. PS3 Media Server is a good choice and very reliable. For Windows 7, Windows Media Player comes integrated and works well most of the time, unfortunately PS3 Media Server is not stable and reliable on Windows 7 from my experience. I hope that they fix this in a future release. Another option that some people seem to like is Tversity, though I haven't played around with it much.

Your best bet will be to try all 3 options out and see what delivers the best performance on your system. I also recommend that you use a ethernet wire to connect your PS3 to your network. The PS3's wifi might work okay for non-hd videos, but as soon as you start watching 720p or 1080p, you're going to quickly run out of bandwdith. Performance in general will be snappier and much faster with wired ethernet.

Hope this helps, good luck.

I just use Vuze.. since thats where I, erm, get all my movies and music. Theres also Tversity, which you can use for free to stream your own files, or pay a subscription fee and be able to stream from the interent like from Hulu. I know even Windows Media Player shows up when I search for media servers so I imagine that would work as well?

There are multiple options, as has been mentioned: PS3 Media Server, Windows Media Server (WMP), there's also TVersity which I use, and some people even use Nero media server software. You'll need to determine which one works best for you as each person has his or her own preferences.