[boswd]

the new nook str (touch) and the kobo touch are the two that comes closest to meeting your needs.

both are eink, both have touch user interfaces, both have less flashing than the kindles and Sony's. Both are very very light.
Both will see good update support
nook has the edge on accesories
nook str has forward and backward page buttons on both sides the kobo does not.
the nook also is more easily hackable for your "tinkering" since it's an android OS.
the kobo has the edge on more file support and better stock PDF, but if you are into rooting then you can install great PDF support for the nook STR.

both feel great in the hand

if you have a Barnes and Noble close by check out the nook STR there, if you have a Best Buy I think both the new Kobo and the new nook are there as well.

Those are the two I think give you the best options of what you are looking for.