If you're just starting out and want a single piece of software (and are prepared to pay about circa US $100 for it) which has an easy learning curve (no techie knowledge required) and can deliver stunning results, I'd recommend Serif Drawplus X4, or Xara Extreme. You can download an earlier version of Drawplus free from their website and have a play. That said, Gimp and Inkscape are free (and very well supported) - and it's hard to beat free although both Gimp and Inkscape require some time investment and slight techie knowledge.