So, it turns out that ownership of Bryce, one of the main 3D rendering programs that I use, has changed hands from Corel to DAZ Productions. I've been using Corel's last version (5.0) for years now, but DAZ has put out two major releases since the version I had been using. Turns out that the first of those versions, 5.5, is now offered completely for free. If you ever thought you might like to get into 3D landscaping, here's a great chance. Additionally, through the 30th of June DAZ has all of their Bryce content on sale for incredible discounts. You can actually upgrade their free 5.5 release to the later 6.1 release for only $20, which is ludicrous. Normally this sort of software is $100 at least; I think they are trying to increase their audience.
On an unrelated note, if you haven't tried Google Sketchup, you might like that as well. It also has a free version, and is even easier to get into than Bryce. Sketchup is particularly useful for modeling objects or architecture, whereas Bryce is more about landscapes, trees, water, and atmospheres/skies.