Welcome Korbein
I think you will see a lot of different techniques on this site, and various applications used to make those maps. Different apps seem to be suited to different styles of map. I use GIMP for mapping (with a bit of help from Inkscape) and when it comes to power its incredible for mapping, and I think its unrivalled (Photoshop users feel free to chime in here). Its just my personal view obviously, but if you want to see some examples of the type of mapping its capable of just type "RobA" into this site's search engine.
Have a great time here, and feel free to ask any questions you have regarding Gimp.
Torq