now you know what can of worms you have opened here. but it's ok the question you ask is a simple one but the answer is very difficult.
you see you have jr guys and futaba guys etc etc. that begins the debate and so on and so on.
the best answer///// depends on you and your needs, if your heart is set on flyin rc the rest of your life then get as many channels as you can. you will want to add flaps gear spoilers etc later on, but you dont know if you want to fly forever do you. then we dont know what advances or coming out either.... do you see why its a hard question to answer?
as far as operation of your aircraft goes any brand will do. i have futaba, ive taught on JR.
the answer that 4 channel gets you flying is so true... I suppose the number of channels depends on your pocket book. if you buy a computerized transmitter then your set for as many planes as you have memory for.
the main thing to remember is have fun good luck