They show signs of interesting ice geology, some of which may be driven by tidal heating. There are also many smaller satellites, including shepherds in the rings.
Titan is a major satellite, only slightly smaller than Ganymede.
It is the only satellite with a substantial atmosphere, one that is more earthlike in many ways than any other in the solar system. Cassini has a radar mapper, similar to that used to map the surface of Venus, that will be able to see through the clouds and study the surface. There is also a lander, named Huygens, that will land on the surface of Titan to study conditions there. Uranus has five satellites that are about the same size as the group of six Saturnian satellites mentioned above. It also has a large number of much smaller moons including possible shepherds.