I would definately recommend going 4 channel from the beginning. The Apprentice 15e is a good trainer for electric. Many of my students use them. They are good up to about 10 mph wind. Beyond that, students tend to stand down because its too much trouble concentrating on learning to fly. After you've soloed and are competent, the plane can handle up to 15mph winds. But its not much fun to fly in that kind of wind. My recommendations generally follow:
Electric - Alpha 450 and Apprentice 15e
Glow - Hobbistar 60 and Alpha 40

I try to keep them away from the Nexstar. The landing gear is not very durable. If you hit something, it rips out the mount and you're done for the day with repairs. This happens more than you might think. We also remove all that self help flying equipment. It just gets in the way and hinders your real learning.
The wire landing gear on most trainers is best because it just bends. You bend it back to shape and you're ready to go again.
Ewdin