Andy, I use Photoshop. Have for about 12 years and have my bachelor's in web design and multimedia. I'd be more than happy to help you out or answer any questions for a fellow artist!
I'm on somewhat of a hiatus from my chosen profession, but my old portfolio still has a few things in it at http://shad0wst0rm.invalid.com
In my honest opinion, I would suggest separating yourself from 'Sigs'. They will not help you in the long run. If I were you, I'd do a quick search for some Interface tutorials and what not to learn more about fine tuning effects and Photoshop's abundance of awesome design tools. Anything but sigs, really. I'm not saying yours are bad. Pretty nice in fact. It's just tough to hone your skills when working with such a small canvas. :-)
Keep at it Brother! You're doing good.
CoolestDude, nice C4D work. I'll be the first to admit, it gave me a run for my money. It can be a tough learn. Luckily I had 3D Studio Max to go running back to.