Hey,
Just thought I'd share this - To those still waiting, it is tough waiting but I am sure Farnell / Element 14 will deliver your Pi's soon, I ordered early April and it was delivered last week.
So far I've tried Debian, and Raspbmc, and it is a great little device.
I'd definitely recommend Raspbmc for media centres, it has some great features - I was able to stream 1080p video with the Youtube plugin and it streamed, and played it back beautifully, not a single dropped frame.
Debian on the other hand is actually rather slow, it's not hardware accelerated yet so just opening up the file browser uses 100% of the CPU, I hear work is underway to get the GPU in the mix though - I think that'll open up a few more possibilites for the Pi, such as being capable of running light-weight games (Something I'd love to get into, perhaps having something like Ubuntus application store where you can buy small games, and other things).
