I'm with K.M. Alexander. My son was doing a graphic design course years ago and got Adobe CS4 at the student rate, I've been using it ever since. I'd like to do more with Ai - some of the things you can do with it blow my mind but in some respects it's harder/more work than Ps.

Dependant on your budget and whether or not you want CAD style maps (CC3) or more 'hand drawn' maps i'd just stick with public domain software, GIMP, Inkscape for example. Regardless of what road you travel there will be a learning curve, admittedly some are steeper than others. When I eventually replace my 12 year old Mac, there is a distinct possibility that the Adobe CS4 may not run well on it, in which case I'll be using the aforementioned software.