Definitely go for the computer radio. A 6 channel is good, and if the budget will allow get one with more channels. You will most likely not be using the extra channels right now, but if you decide to use flaps, flaperons, retracts, smoke, etc you will need the extra channels. I also appreciate that you can store the settings for several planes in the same transmitter.

The 6EXA is a decent computer radio. Personally, I would spend a little extra money and get the 6XAS. Overall, I feel the 6XAS is a better radio. It has a more "solid" feel to it and doesn't have the "cheap" appearance of the 6EXA.

To hook up 5 servos to a 4 channel radio use a "Y" connector.

I have had excellent results with the following for servos and flight packs.

http://www.balsapr.com/

http://servohut.com/

http://servocity.com/

Hope this is of some help.