get Photoshop CS ( which is really PS 8) but thats just me being silly... i think you might have more than enough all ready. get to know the programs you've got now... once you've mastered the basics of them, then maybe you can get more and more.. till your computer is bursting at its electronic seams.. and your wallet is as empty as mine!
There is one, and its not very common on this website... But Lightwave 7!
That will set you back $1600 American......
But i've seen some stuff that comes out of it!! AWESOME...
Take this Tour
http://www.newtek.com/products/lightwave/product/index.html
Or Check this out!
http://www.newtek.com/products/lightwave/product/feature_list.html
Here are some things you would have heard that lightwave was used in...
http://www.newtek.com/products/lightwave/product/projects_list.html
I agree with Grim^^. and some of these programs ask a lot to your computer, like photoshop 7. If I were you, I would just use Photoshop (and the plug-ins), Bryce and Paintshop Pro. You don't really need corel if you have photoshop, and terragen if you have Bryce^^.
Is there anything I havn't got yet?
P.S. Just cause I got em, doesn't mean I can use em =D