RE: best second airplane
In the 4 star and tiger and pulse style, there the phoenix model [link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXLGM8&P=ML]dolphin 40[/link] (100$), it's a great little aircraft landing a little bit faster than a regular trainer but quite easy to fly on low rate.
I've try a super stick from Hangar 9 too, and I do prefer the dolphin. But for someone that just soloed I would recommend the stick, handled a little bit more like a trainer.
And I agree with the other keep your trainer flight ready. Take a "cheap" airframe, but a flight pack [link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXKYL2&P=SM]Hitec pack[/link] with another engine (new) of your choice, like the [link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXJA86&P=7]tower .46[/link] (90$). Don't forget the [link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXN503**&P=M]Rx crystal[/link] (8$)
So for about 298$ you could get a nice flying plane (and there some instant rebate you could get)