First thing you should do is go into the kit building forum and look around. This same question is brought up a lot there, just this week too. Most of us have a favorite kit, in my case I teach building using the 4* 60, easy plane to build and a good plane to fly. Depending on the students ability at flying I do a couple of mods, I remove two wing bays to make it a bit more responsive in rolls. Before someone turned me onto the 4* I used the GP Super Sportster 60. A little more involved in the building but a much better stunt plane compared to the 4*. For a real hoot I would build the GP Up-Roar 40. A bit smaller and uses a .40 to a .46, even the OS ,55 would be great in this plane. It cost under 50 bucks and has a 48 inch wing. Designed for Fun Fly events it will do everything and once you put the engine on idle it will float like a feather.
Go to the kit building forum and do a lurk, just check out different threads. Go back several pages, there are a ton of second plane threads to look at.