If you could write an OS from scratch...

Okay, so most every OS out there is C-based.  If you could magically write a complete hardware-controlling OS all the way up to the UI and applications using a different language, which would you choose?

Though I like Lisp, I think I'd have to choose Erlang, maybe NewSqueak for embedded/smaller systems.

Very-High-Level: E
Super-High-Level: F
Maximum-High-Level: G
Impossibly-High-Level: H(askell)