Saturn

Titan

Titan is the principal settlement of Saturn. Unlike most satellites Titan came pre-equipped with an atmosphere comprised primarily of Nitrogen and Methane (very much like Earths early atmosphere). The methane provides a minor 'warming' effect on the planet, allowing for the presence of liquid ethane seas.

Research installation orbiting Saturn performing pressure experiments in how to extract some of Saturns' liquid-metallic Hydrogen core.

Enceladus

Enceladus is the 'water world' of the Saturnian system. Its development has thus far been limited to water exporting stations. But there are proposals to expand the limited infrastructure to support a permanent population of several thousand.

Tethys, Iapetus, Dione and Rhea

All four of these moons are rocks with extensive mining interests and some habitats.

Triton:

Uranus and Neptune are currently undeveloped, with the exception of Neptune's moon Triton.

Triton is fairly unique in so much that only it, Io, Venus and Earth suffer active volcanism. On Triton, this volcanism is in the form of Ice geysers and earthquakes. As a result about 150 Scientists and Engineers are currently on Triton performing evaluations into its suitability as a future human settlement. They are also strongly recommending that Triton be developed for its water and ethane resources.

The greatest drawback to the further exploitation and development of Triton is that it is simply so far from everything else.