What should I keep my angelgotchi's AP at? It is a toddler.

Look here: http://tama-zone.com/index.php?showtopic=16372
Basically, if you want an adult character that is higher on the list, keep your AP/TP high. If you want one lower, keep it low.
For more detailed information, lookie here: http://www.mimitchi.com/html/tangch.htm