Not sure if this is too late, but another vote for Alaska!! (Plus, their miles are interchangeable with American).
I used to travel up to Vancouver weekly on Alaska for almost a year, and in that many flights, I never had a bad experience. Even what could have been "bad" ended up being minor inconveniences due to their proactive customer service.
Also, while I was travelling with them, I noticed they often had a "kids fly free" program (to Disney or Mexico.)