ORIGINAL: MikeL
Radios choices are all driven by what you want to do and where your interests are. I fly mostly glow, 40-60 size models. I've got a helicopter that uses 8 channels (too many gadgets!). I occasionally try a park flyer. So for me, I need something with at least 8 channels that has receivers available in many different sizes. I also wanted 2.4ghz. When I bought a new radio last year I had three brands to really look at. Futaba, JR, and Airtronics. Spektrum doesn't make an 8 channel, so it was out. Airtronics has only one 2.4ghz receiver, which is too big for the small park flyers. That left Futaba and JR. For me, it was the wide range of Spektrum receivers that pushed me to JR. I can get a 6-channel park flyer receiver for $40, and a 5-channel full range receiver for $50. Futaba just can't come close to those prices. I've got enough airplanes that paying Futaba's prices would have made my total cost of switching to 2.4ghz pretty pricey.
That's how my reasoning went. You're best off doing something similar for yourself. Figure out your features that you want, channels, and what your budget is. That takes some work and there's really no way anyone can do it for you. Much depends on where you see yourself going with the hobby. If you stick to the major brands there's really not a bad product out there.
Actually, Spektrum does make radios with more than 7 channels, they just put JR on them, or JR makes radios with less than 8, they put Spektrum on them, any way you want to look at it.
Here's how I see it. The largest expense you'll have will most likely be in receivers, as these 2.4 gHz rx are all still pretty expensive. If you are like me, and you have 10 or more planes, then you will easily spend over a grand on replacing all of you rx's (over time), while the radio itself will cost you anywhere from 150 to 4 or 5 hondo. I like spektrum/JR because they (right now) offer the biggest line of rx, for the best prices (IMO). like MikeL said, not all of your planes will need 7 or 8 channels, but with most of the brands you will be limited to one or two rx at most to choose from when you go to start buying rx's. With spektrum, you can pay as little as 49 or 59, all the way up to whatever you want to spend on a rx, depending upon the application. So if you see yourself needing more than 7 channels, get the 9 channel JR, as it will use any of the JR or spektrum rx on the market today (because they are all the same).