Until a whistleblower leaks the key, it won't be possible to liberate the ME.
Once the key is leaked one could write a free replacement firmware using gcc.
Therefore I won't buy the hyped hardware, which I think is as bad as
Raspberry Pi. The Rasperry Pi firmware uses a proprietery instruction set
which is not supported by GCC. The only thing that you can do with the
Rasperry Pi without using any nonfree software is getting a blinking LED.
Writing free microcode is impossible without knowing the microarchitecture of
the CPU.
Currently the best way to have full freedom is the Gluglug which has the ME
disabled. It has some minor flaws that you cannot use KVM, but there is XEN
which allows virtualisation of free operating systems. It should even be
possible to run the GNU Hurd[1] side by side with GNU/Linux. Hardware
virtualization is designed to virtualize proprietery operating systems, I
think there is no need for hardware virtualization in the free world.
On the long term one should migrate to architectures which do not have an A20
gate[2] such as ARM, MIPS or POWERPC.
[1] http://libreboot.org/faq/#gnuhurd
[2] https://en.wikipedia.org/wiki/A20_line
