We have good imagery of this moon, because Cassini spacecraft was flying around it from 2004 to 2013.
The moon has valleys, lakes, and mountains. But the lakes are from hydrocarbon, not water.
Most of the liquid is concentrated in one region of the moon, covering an area of 600 X 1100 miles. There are smaller lakes outside of this area, but they comprise only 3% of the moon's liquid.
Two major seas of Titan are called Kraken Mare and Ligeia Mare.
Recent attempts of Cassinni to probe the depth of a sea on Titan were successful. It was able to determine that the depth of the Ligia Mare is about 560 ft. Supposedly, the surface of the sea may be as smooth as the paint on a car, which made it possible for radars to peer through it.
Total volume of liquid hydrocarbon is now estimated to be around 2000 cubic miles, which is 40 times more than all of known oil reservoirs on Earth.
It's fascinating that we are able to actually see these other worlds up close, to see that they have remarkable surface features, that look similar to our Earth. It's just a moon, yet it has lakes, mountains, and valleys.
That doesn't mean that it is ready for colonization though. From the video animations made by NASA, you almost could feel ready to go for a swim in those blue-colored lakes. But don't jump in just yet, hydrocarbon is not good swimming material.