For rendering landscapes, Terragen is the best. After trying both Bryce and Terragen - I really could never get my landscapes to look as nice in Bryce. They always ended up looking low-res and the textures always just looked wrong. You just can't beat the per-pixel detail of Terragen. It's not freeware, however.

Otherwise, I play around with these programs:

• Art of Illusion is a decent open source renderer/modeller. Not as high end as Blender, but pretty easy to use.
  
• Blender is about as professional as you can get for the price of $0. The user interface, however, is a lesson on how not to design user interfaces. Everything is a button, and it's got a steep learning curve.
  
• SketchUp is nice for drafting designs, but it's got a steep price if you want to export to another 3D program and use it commercially.
• Wings3D is great for creating models with.
  
• POV-Ray is interesting in that your scene is essentially a software program, and it directly renders true mathematical shapes rather than converting them to polygons.

If memory serves, it is nearly impossible to get a Bryce wall into the galleries here.

There are some really beautiful Bryce renders submitted at cgsociety.

Terragen is tough for me and I read in a review that it doen't import models and can't create trees.

d-grafix pro terrain is one of the most recommended at gamedev.net and it can create trees too. and is also cheap $31.

Not true...Most of my walls are done in Bryce...

Yeah, I'd have to say that blender is definately my favorite program.  While it takes a while to master, it has most any feature you could possibly want and photo realistic rendering.  To top it off, it's free!

The application isn't the issue, it's someone pushing two buttons and then uploading it.

The 'simple' trick is to ensure the wall does not APPEAR to have been made in Bryce.

It can be done....

Also almost all of richard mohlers walls are also done with Bryce

Who needs walls when we have open space just by taking a walk outside in full 3D reality (today, it's snowing like hell & i could render it in Bryce -- or not -- too!)

Life is Art.

Second that, it's an exemplary reference of highend open-source while being sooooo free it's mind boggling (takes a lot of time & brain energy to learn, but for the life of me IT simply won't handle GC2 directX models how it c_should!) -- but, NOT... for Landscaping as per the OP's request for advice.

Thank God, you don't moderate walls.....

Otherwise everyone would have to write....."Not Rendered In Bryce"