I'm sure you are aware of it, but I have just one minor note: There seems to be some graphical issues with the rivers coming into that lake roughly in the middle and 3/4's down the page. Also some rivers stick out a bit into the ocean.
I tried doing mountains that look that good a bunch of times unsuccessfully. Eventually just resorting to stealing Earths and then changing it to suit. How did you manage to get it working so well?