is hard to beat, but its offspring Cinepaint
is Hollywood's sweetheart. (Note Cinepaint's usage in the creation of such movies as Harry Potter series and 2 Fast 2 Furious).
You might want to try Blender
for 3D modelling.
Commodity software is the opposite of manufactured goods: The best available is completely free (price and source). The reason is simple -- every user has the potential to improve free software, by documentation, by noticing and reporting a problem, by direct coding, or by passing a copy along to someone else who might do any of those things. (It's why Pixar, Sony, Industrial Light and Magic, Dreamworks, Mercedes, VW and so many others love it).