For a basic guide pick something with one engine, wide landing gear and the longest nose available. Keep the tail light. From what I have read most ARF's are sport planes dressed up to look scale. They probably don't fly like a true scale bird because of weight, scale dimensions and air foil. Platt has some great designs which I find to be a very good size, you should look at Skyshark and of course Top Flite.

Of course you could have a warbird Cub, Chipmunk or PT-XX which are very easy to fly.

Carl