RE: Looking for advice in choosing my first Trainer
My 2 cents would be for any of the Sig's Kadet line. I'm partial to the LT-40 but any of them would be good. I'd reccomend getting one with ailerons. Also make sure you take some time and work on a unique covering design for either the top or bottom (not both) of the wing. This will help you keep orientation in flight. I put a red fan pattern on the top of my white wing and it's hard not to tell which way the plane is going.
For radios I'd reccomend one of the 4 channel computer radios. It might cost a little more, but it will give you more flexibility as you keep getting deeper into the hobbie. I have a JR 421ex and I love it. It has a two model memory and is accually a 5 channel radio (you can have retractable gear, etc if you want).
For an engine for the LT-40 I'd reccomend any of the .46 size. I have an OS 40LA in mine and it's starting to be too small an engine for me, so I'd go with a little bigger engine to start.