Not me, you guys. My own talents for visual imagination are horribly lacking, and some of the stuff here simply boggles my mind. I struggle with even the most basic of buildings, and here I find photo-realistic satellite imagery of fantasy realms. So very, very jealous, and so very, very cool. I don't know how much I can contribute beyond appreciation, but know that it's very deeply there.
Be sure to check out the tutorials, a few runs thru some of those and you'll be cranking out quality maps of your own.
Welcome to the Guild. AS SG said, there are many many resources here to help you learn and them master the craft. Try some tutorials and don't be afraid to post a Work in Progress it's the best way to get direct feedback. :)
welcome to the guild - and as jtougas said, if you make a WIP thread for your work, you can get input, help and critique while you work on it - we'll have you cranking out maps in no time :)