Named for a race of mythological giants, Titan is just that. Titan is a very large moon, and it was given its name because it was thought to be the largest moon in the Solar System. However, more recent figures place Ganymede as the largest. Still, Titan is a giant among moons.
Titan is unique among the moons in our Solar System because it actually has a significant atmosphere. This atmosphere allows for chemical reactions which convert methane into ethane and eventually into more complex organic matter, which falls to the surface. The scenario is surprisingly similar to the "primordial soup" thought to have spawned life on Earth.
Unfortunately, the same thick atmosphere that makes life a possibility on Titan also makes observing the moon a chore. Thick clouds cover our view of Titan even from close distances, making it very difficult to learn more about it. Life may someday arise from Titan's organic goop. Anything that lives there must be able to survive the cold temperatures, but nature usually finds a way.
* Photo credit - NSSDC Planetary Image Catalog