I like the Microscosm series from RDNA..it allows terrain directly in Poser without having to buy Vue or Bryce, or another higher end software. A bonus, it can be used in other programs to expand those as well :) Also their naturals, grasses, trees, etc...great stuff

Humankind has not woven the web of life. We are but one thread within it.
Whatever we do to the web, we do to ourselves. All things are bound together.
All things connect......Chief Seattle, 1854