With hopping the break even between regular tickets and an AP is about 13 days.
If you set aside some days for water parks and Disney Quest only, you can get 12 days of Disney fun or even all 14 consecutive days (up to 15 if non-expiring) out of a 10 day pass with water park fun & more.
If you anticipate a trip after this one that is more than a year away you could get one 10 day expiring pass to use up completely and then start on a second 10 day pass, this one with non-expiration. If you expect another trip less than a year away you should get AP's now (using 12 days now and some days later).
From time to time 14 and 21 consecutive day promotional Disney passes are available from non-Disney sources. Currently I don't know of any for sale in the U.S.
Seashore--maybe I should consider what you said and get the plusses. We are going in January and it's too cold for water parks but maybe we could hit Disney Quest a couple of different days... I'll have to check and see what the plus passes would cost extra. Honestly, if I'm going to start over with tickets (like a two day) I'll just go to Sea World or Universal or something...
Disney hints:
http://members.aol.com/ajaynejr/dispass.htm