L4-L5 and HEO

As I remember, the 2:1 orbit was highly eccentric, between a few thousand
km high to around 2/3 of the way to the Moon. It was resonant in that the
Moon's tug pulled it around the Earth every 2 weeks, keeping it stable and
predictable against the various tugs from other planets, etc. Otherwise known
as HEEO (high/Highly Eccentric Earth Orbit).
It was favored both for that stability and the delta-V requirements to get to/
from it, from various other places/orbits like Solar space and Earth and the
Moon. HEO is usually only ~500 miles up, where LEO is only less than 200,
and is subject to atmospheric drags.
I like to keep in mind the mechanics for throwing payloads between and
among such orbits with rotavator tethers. One in LEO (or a hypersonic
skyhook) tosses it up to one in HEO, which can either pass it on to HEEO or
interplanetary space.
Scientific American
Space Tethers
By Robert L. Forward and Robert P. Hoyt
http://makeashorterlink.com/?D2B032E96

Personally, I like the Jupiter/Sun L-4,5 points... Plenty of resources and free
space, with a good view (10 AU baseline for interstellar interferometry
observations.) Somewhere in the Oort cloud is even better! Obviously not the
first habitat.