Hmm, Gimp is fairly decent for a Photoshop alternative. I know pros won't be switching, but I'm proficient enough with it that I still prefer it now.
However, Gimp won't cover Illustrator. Inkscape does a damned good job with SVGs.
I'm a scientist, not a designer, so these cover the needs of me and my lab for no cost. I can do nice looking posters and whatnot with these tools, quite efficiently.