I use both Photoshop and Gimp so it depends on what I am doing as to which I use. As others have noted PS is more appropriate for professional graphic artists and Gimp more towards hobbyists.
The site needs a little reworking with color, typography and maybe a little reorganizing. It's got a decent base layout that I think really just needs a bit of tweaking to make it shine.
Some suggestions:
The header is a little difficult to read and doesn't clearly define what exactly the...