It all depends on what kind of wallpaper you want to create! For my fractals I use Ultra fractal and paint shop pro 7, Some people use Tierazone, apohpysis, and Gimp wich are free softwares.
Other use photoshop. All of these makes great wallpaper. But the very best thing you need to create a great wallpaper you have within yourself, it is your imagination! With a little tutoriel and a lot of imagination you can get anywhere! Have fun!
Tricky Q... Impossible to tell in a way. Perhaps one can say: The one you can handle and (/ or learn to handle, and) the one you can get hold of. If you like me are a mere mortal with no big cash at hand you'll have to do with free (or cheap) software, there are a thread on those somewhere on this discussion board. You can also, like me marry a nice graphic designer that can afford to bye the heavyweight programs like Photoshop. ^_^ I'm betting you'll get better advice elsewhere.
I am like Yin & Yang, my lighter side is balanced by my darkerside, embrace both & you get the whole me, play with one & you will meet the other...
www.ganjataz.com ~ www.ganjataz.co.uk
And lastly, View an image, vote on it, then bloody comment on it. How else are we artists to know what you like or don't if you do not tell us?
"The whole problem with the world is that fools and fanatics are always so certain of themselves, but wiser people so full of doubts." Bertrand Russell