This comment may be a little off-topic but all the exclusive attention on the Pi frustrates me a bit. It's a very limited piece of hardware: the SoC is uses spends almost all of it's transistors on the videocore unit which is basically not useful to the FOSS world. (Unfortunate— as I understand that it's a pretty neat and highly flexible architecture, but entirely proprietary)
The arm core is rather slow for what it is— cache deprived and an older microarch it is clock for clock much slower than the current fast arm stuff in tablets today while running at lower clock and with only a single core. People are often trying to ask it to do more than it realistically can.
Sometimes this is because they're unaware that there are alternatives in similar form factors for somewhat higher prices which are enormously faster, such as http://www.hardkernel.com/renewal_2011/products/prdt_info... (quad core 1.7ghz 2gb ram, $89) which would better suit some of these applications. (though indeed, the pi does seem to be king for applications where price trumps all other considerations— including the openness of the platform— and yet you still can't use an actual micro-controller).