While it's true you can still buy the
DDP and have an AP you must give up the AP room discount and pay rack price for the rooms and a one day ticket must be purchased for everyone in the room, not just one person. I have an AP, but it's main benefit is getting me in the park several times a year. I've used the DDP with it three times (
free dining in Sept '05 and Sept '06, and purchased in May '06), but again have had to purchase a one day MYW ticket for everyone in the room each time and was unable to use my AP room discount on those trips. I'm doing the same thing this Sept--free dining is a better deal than the AP discount I might get.
Your one day tickets are good forever as long as you never put them in a turnstyle. You can always use them the next year and upgrade them to another AP. I did that last May. If you have an AP you can also buy (for $60.00) the DDE card which will give you 20% off most TS restaraunts and a few CS (AK and resorts that don't have a TS option). It will pay for itself in a trip or two.
As far as getting an AP room discount you now must have an Adult AP as only adults can make room reservations--Disney has really cracked down on this. There are also times of the year when AP discounts may not be offered--I believe last June and July were times room discounts were not offered for AP holders. I'm currently waiting to see if an AP code will be offered for my May trip. If so, I'll go with that and use my DDE card, but if not then I'll upgrade my room only to a pkg, add a one day MYW ticket, and buy the DDP.
You can also get AP discounts at the Basin, World of
Disney store in DTD, backstage tours, Richard Petty Driving Experience at WDW, etc.
I love my AP, as it seems to have a habit of calling and booking extra trips I probably would not take otherwise

, but it's main benefit is getting me into the parks. I also like the hopping option it give me.