SIG 4* 40/60/120 kit is the perfect 2nd plane and/or aileron trainer. I have a cousin who was in the hobby for 15 years and this was still bar none his favorite plane (40 size).

Ultra Sport 40/60/1000 kit are touted as the best flying sport planes ever made. They fly so well you can fly pattern with them as well. Extremely aerobatic and fly on rails. You'll be hard pressed to find a better flying sport plane.

Other good options are a Super Sportster 40/60, J-3 Cub, Stick Series, etc.

I suggest you check out the kit building forum and do some reading.