Terrain Generation program(s)

I am working on a project which requires top down, random, varied(i.e. mtns., valleys, lakes, rivers, etc.) images of terrain. A bonus would be if said program could also generate weather systems (static), although I can overlay them if necessary.

Thanks in advance for any suggestions or ideas.

Edit: To clarify what I meant by *terrain* I mean as seen from from near earth orbit, far enough away to perceive weather systems, yet not so far away as to indicate you are looking at a sphere.
I don't need any text, longitude or latitude lines. LOL, picky enough?

c/o Kris Ritter in another thread:

Any of youse ever seen Trainz? (http://www.auran.com)

I have never used it, but Kris speaks highly of it.

Terragen.

Thanks guys