Lisbian08, on Sep 27 2010, 09:42, said:
Try the original Droid. It still has by far the most ROMs available. The newer android phones are most "locked down" and not as configurable. You should be able to find one for a decent price these days.
i agree with lisbian but not because i have the droid1...it's your criteria, "cheap used android phone that I can mess with, flash upgrade."
AFAIK, D1 and the N1 are the only STOCK android out of the box--no GUI overlay, no bootlock, etc. this makes them accessible and ideal for the modding community. moreover, because D1 has a 'slower' processor than N1, it will be the cheapest. however, like the omnia, it has a strong mod community that will easily be around for as long as the omnia.
heck, if $$$ was no issue, i'd likely stick with my D1 until battery/charging tech improves--it's the final barrier. higher processor speed and bigger display is meaningless if it makes you anal about battery-drain and OCD for the newest battery tweak/hack.
my 2 cents.