Well so much for my wild-ass guesses, I retract it, mostly.

First, I should have been more clear that when I said I guessed the surface was old, I didn't necessarily mean primordial, like our moon or most of the other Saturnian satellites.

My point was that if there are a moderate number of impact craters, and even some old basins still visible (if modified), and given the lower cratering rate there, then Titan's surface probably hasn't been totally remade since the heavy bombardment ended. Renewed on time scales of a billion years or more.

That is a lot faster than say, our Moon, which would look very recognizable 10 billion years from now at the current modification rate. But also a lot slower than Europa, Io, or Earth, which can erase craters in millions or tens of millions of years.

That being said, the later images and the radar data show fewer crater-looking things, and even the round embayments I was talking about look less circular, more modified in the close range images. So the surface looks less old than my first thought -- but still older than Europa.