OK, One thing no-one has bothered to say. Since you stated that you want a radio for both Heli and fixed wing aircraft, forget about the 72Mhz or other XXMhz radios and go for the 2.4Ghz instead. Reason being, with the XXMhz receivers you have a 1meter or there abouts antenna wire that you have to figure out how to keep from getting stuck in the rotor blades or tail rotor. The only option I have seen for this was to get a loaded antenna and cut the antenna wire to fit. With the 2.4Ghz radios the antenna sets are a lot shorter and easier to mount.

As far as the brand of the radio, I am partial to Futaba, but that may not be the best fit.

The best way to figure out what will fit you is to research the helicopters that you are interested in, See if you can download the manuals and see which radios they reference. Also check for any wierd mixes usually dealing with the cyclic and collective pitches and make sure the radio that you are looking at is capable of everything to get the thing flying. You definitely want a minimum of a 6 channel computer radio.

If you are looking at getting into giant scale aircraft with redundant receivers, the JR/Spektrum radios might not work. From what I have read on here, if you select your model and even though muliple receivers are linked to the transmitter, only the ONE that is for that model will respond. I don't know this for a fact but it is a question you may want to raise if you plan to run multiple receivers in an aircraft.