First of all, I strongly recommend the Apple TV as a device to bring your iTunes content (local or on the store) to the B&O world. It is very B&O-like: You just plug in the power chord, the HDMI cable, and the PUC cable, and everything just works. No software installation, nothing. Plus it is SO much cheaper: 260€ vs. 800€.
The new Mac mini is a strange beast to me: Yes, I like the looks a lot, and the specs are also great. But 800€ for JUST a basic computer? The previous model was ok (started at 600). Remember that you will need additional RAM, a keyboard and a mouse, and you will still not be able to enjoy the (to me) beautiful UI of the Apple TV.
This being said, I unfortunately cannot tell you whether the CPU of the new Mac Mini is capable of decoding Full HD and serving large files over the network at the same time. I assume this mainly depends on the Codec used for the movie file.
elephant:
My concern Christof, is should I just have it as a server ... and get something else as the end-point media interface ?
I would be a lot happier if I new the specifications of the rumoured replacement for the Apple TV.
What was at the back of my mind when I was writing my first set of comments was the new MacMini playing a 1080p movie and then recieving requests from other users for large files ... should I be planning for a separation of duties ?