I finally got my raspberry pi in the mail last Saturday. Today I got time to play with it. Got a cheap HDMI cable, a no-name SD card, the power supply from my HTC and a keyboard and mouse. Plugged in network to connect to my Synology DS110j NAS and I was ready. Here's a shot of it with an AA battery for size.
Decided to try Raspbmc first since I couldn't find a way to install openelec from a windows machine. So I got the installer and pointed it to the SD card. 10 minutes later it was done. Plugged it into the Raspberry and watched it boot. Familiar linux style boot after which raspbmc started updating. I left it running for about an hour.
After that I found that I really know nothing about XBMC. But, the raspbmc project is reasonably well documented. So add some sources, discovered that you need to tell it to direct sound to the HDMI port and not some fancy receiver. A few minutes later I was watching some downloaded content. Most things work, high res mkv files do put a strain on the little processor though and there's the occasional sound problem.
I'm now watching an episode of "the Hairy Bikers" that I downloaded several weeks ago. Sound is good, picture is very, very crisp.
I need to tweak this, find a way to remote control and see if I can do some tuning for speed. Still, a very, very promising start. Tomorrow I'm going to try openelec using this guide.