RE: good second plane
A lot of so-called good 2nd planes end up in the dumpster because their wing loadings are too high, so mistakes in judgement get amplified and second chances are rarely doled out.
A great second plane would be a .15 powered Slow Survivable Combat plane [SSC] like the Lanier Ripper or Treneff RC BattleAxe. 600 some odd sq inches and 40 ozs RTF. Aerobatic enough to be fun and a plane that you can land at your feet. Add a rudder to enhance spins and tumbles. These planes are versatile and will gladly accept .40 sized engines when you're ready. The key to having a low impact, low investment experience while you learn is to not get into too much plane too soon.
Another route to take if you have a taste for 3D is to go ahead and get a profile plane that specs out no heavier than 4 pounds [RTF] with about 600 square inches of wing. I would recommend taking a look at Ohio Model Products offerings.
Don't over look a SPAD type plane, the trade off is low investment, low build time for a plane that might not fly as well as a balsa counterpart, but great for an instructional tool.
Once you get some time under your belt, a great 3D trainer is the 24"x24" Pizza Box Flyer.