"Despite the fact that this is one of the least popular (among
non Linux enthusiasts) in the list, I personally would like the
Freerunner to keep this spot - the top. The reason is pretty
simple: It's the most hackable device among the 10. The thought of
being able to customize it, making it truly your own phone, just
fascinates me. You may download the source code as well as other
references and resources from their wiki site.
"Here's more good news. The Freerunner can now run on the
Android operating system. Yup, the same OS that runs on the G1.
While the default OS is Openmoko Linux, other distributions can run
on this phone as well. Some of them are Qt Extended, Gentoo, and
Debian."