I was just fiddling around a couple days ago and made these landscapes with Terragen (to be imported to Lightwave) http://www.flickr.com/photos/19601859@N00/ This program couldn't be easier to use. Also, you can upload real life maps and use it to make animations in other programs using your city's real landscapes
I used to have the program. Unfortunetly, I never got used to how it worked and couldn't create anything that looked really good and got rid of it.
I use this program all the time and I learned how to use it. It is kind of hard to create texture maps but its fun to use.