Cheapest I have seen using voucher code.
Wi-Fi (802.11 a, b, g, or n) wireless network (wireless video streaming requires 802.11a, g or n) or 10/100BASE-T Ethernet network
iTunes Store account for renting movies and TV shows
Netflix account for streaming Netflix content
For streaming media from a Mac or PC:
iTunes 10.0.1 or later; iTunes Store account for Home Sharing
Our most entertaining design yet.
The sleek new Apple TV has been completely retuned for your entertainment.
It’s 80 percent smaller than the previous generation — even with a built-in power supply. Which makes it perfect for sitting neatly on a widescreen TV stand or squeezing into a crowded media cabinet.
Not only does the new Apple TV have an amazingly small footprint, it’s also incredibly energy efficient. It stays cool without a fan, so it’s never noisy
And when it’s not filling your living room with drama, romance, and comedy, it uses less power than a night-light
Technical info - http://www.apple.com/uk/appletv/specs.html
As it's been raised multiple times in various threads:-
Yes it runs XBMC
Yes it decodes 1080p mkvs (with some skipped frames on high bit rate files)
No it doesn't output in 1080p - only 720p as it's a hardware limitation:)