My flat-mate purchased one of the new "slim" 360's the other day and though I had no interest in it, I found that it is a convenient way of using the Sky Player rather than having to physically go over to the media pc and use their software, or search endlessly and without result for a way to get the Sky Player into Media Center. Seeing as the 360 can also be used as an extender, and it must have an infra-red port hidden away somewhere as the Windows media remote works perfectly, we decided to run everything on the 360 so that we wouldn't have to constantly switch channels.
We already have an ethernet cable running from the media pc to the router in the hall, and adding another cable really isn't practical, so at first we just used the wireless adapter inside the console. This did not work well at all - even though it connected to Xbox Live perfectly, and gave a perfect connection signal there, it reported a very bad connection to the media pc and once I got it to hook up, was extremely slow. I managed to get a single .mp3 playing, but video seemed to be out of the question. I decided to add another network card to the pc, hook the 360 up to that, and bridge the connections. This worked perfectly, without my having to give the 360 any IP addresses and what-not.
However, Windows Media Center on the 360 is still extremely slow. Even though it reports a perfect connection, with bandwith at the very top of the graph (more than suitable for streaming HD media), navigating the menus is a painfully slow process. It did manage to launch Tunerfree MCE without any issues, and I was able to watch an episode of Lab Rats on MSN, but I still haven't been able to watch a video on the media pc's hard drive as the whole thing comes to a halt after a few minutes slowly browsing the menus. In fact, the last time I tried, it refused to connect to the pc at all. In the network tests available on the 360, it connected to the Internet and then the pc with no problems, but connecting to the pc to launch Media Center failed. Kinda inconsistent results, right?
I was confused about the failed media streaming over wireless, as the laptops in the apartment have no issues streaming even HD media over wireless G (which is what our router supports), and even the Wii, which is sat next to the 360, has no issues streaming either. But when the connection is almost as bad over a 100Mbps ethernet cable, something must have gone wrong somewhere.
The media pc is an Acer Aspire M1610 with a Pentium Dual Core E2160 (1.8GHz), 2GB RAM, three hard drives (1x 80GB Windows PATA, 2x 1TB SATA), and two network adapters, one onboard and another a PCI card. Both are set to allow RTX flow control and full 100Mbps negotiation, bridged and connected to a Netgear DG834G router/ADSL modem, which in turn has a Canyon eight port ethernet switch plugged into it. The 360 is connected to the pc via a cross patch cable, which I bought before I was aware of the 360's nifty auto-sensing feature.