Hi, thanks for your reply,
I am a bit new the Linux MCE, so i'm not 100% sure what you just said lol, i'm just after an out of the box Media Director that will just work, but I need it to mount behind TV?
UI1 is the default simple user interface. It's basically what you will see via web interface, web pads, etc. In short, it's intended to work pretty much anywhere with slight differences in button location etc. on any graphical interface (called an orbiter). On the downside, it's not very attractive. Due to limitations in the linux drivers for the graphic chipset that comes with via based motherboards (Chrome), it's not a great choice for linux in general or LinuxMCE specifically.
Most (all??) of the new Intel Atom processor based boards come with the Intel 945G graphics chipset which is much more promising. The Asus EEE computers that Bulek mentioned are an example of an Atom/945G based system. They are also very small and similar to the via based boxes in terms of target market, small media center frontends (MDs) for example.
Beyond that, I'd suggest you read the wiki as well as search this forum for longer more detailed discussions of these systems.