I'll just add my 25c in that Geocontrol is awesome. I bought version 1, have been playing with the beta of 2, and the only reason I haven't bought 2 is that I can't yet since it's not released. I still have some difficulty getting just what I want because the tool is so powerful, but I'm improving. The roads tool and the water tool are unbelievable. (The water tool is really slow, because it simulates water flow.)

For mesh modelers, I suggest trying the demos of several and going with what you feel comfortable with. They all have different approaches, some appeal to some people and others appeal to, well, others.

The instructional videos for modo are very well done. You get a free one - modeling a sea horse - when you buy the product (at least at the time I bought it you did) and the Andy Brown videos are in my opinion well worth the price. He makes it look so simple!