As the father of a two year old and a long-standing US Airways FT'er I am really pleased with the constructive information and opinions given in this thread. ^
My daughter just turned two last month and has already flown LH C to Europe and numerous domestic flights between DCA and PWM. We try to be very attentive parents and are fortunate that she is not a big tantrum tosser. It has also been very fortunate that the flights between DCA and PWM are right at her nap time so more often then not, she's sleeping or reading a book on our laps. Now that she is two, she'll have her own seat and US DM account as well!