Channels determine how many different controls you can have along with how many automatic mixes. A trainer needs 4, while most sport planes need 5 or 6. If you start with a 6 channel computer radio it will be enough for at least your first 2 or 3 planes. The Hitec Optic 6 is a good value. For the rest of your shopping list, a Hobbico Avistar is hard to beat if you will be working with an instructor. The above mentioned OS .46 AX is a great engine, but I'll recommend a Thunder Tiger ,46 pro because it's nearly as good and 1/3 less expensive. You'll also need a field box, which includes a starter (preferably wireless) and a glow driver, glow plug wrench, and hand tools.