For general all-purpose graphic editing, manipulation, and creation, Adobe Photoshop is hard to beat. But JASC's PSP8 http://www.jasc.com/products/paintshoppro/? is in my opinion, very nearly as good, and I actually am finding I like it better for some things. CorelDRAW http://www.corel.com/servlet/Satellite?pagename=Corel2/Home is also a very good full-featured graphics program, which I prefer for vectorbased drawing tools. The GIMP http://www.gimp.org/ is free, and also full-featured, although it can be quirky and difficult to learn.
For 3D stuff, I prefer 3ds max by discreet http://www.discreet.com/3dsmax/
There is also Rhino: http://www.rhino3d.com/
And Lightwave 3D : http://www.newtek.com/buynow/lw_products.html
And Maya: http://www.aliaswavefront.com/eng/products-services/maya/index.shtml
And POV-Ray: http://www.povray.org/
And Terragen: http://planetside.co.uk/
The last two are free, but are quite good once you get the hang of them. There is also Bryce, as you mentioned, but PLEASE do yourself a favor and read this thread https://www.wincustomize.com/msgboard.asp?BID=WCS&id=178969#185533 and check out the links provided there if you decide to use Bryce.
Finally, if you decide to become a wallpaper artist and upload here to WinCustomize, please read the site FAQ and this thread: https://www.wincustomize.com/msgboard.asp?BID=WC&id=253773 )
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