So I know people love free dining. LOVE IT. However, I've done a lot of math, and free dining isn't always the best deal (let alone the DDP in general). I think people tend to forget that it's not really free (thus the quotation marks above), since you have to pay rack rate on a room that you could otherwise get discounted. Thus, instead, it's an alternative discount. A lot of the times, it is a better discount than one of the other deals you could get, but it's worth doing the math.
You can read more about this, plus my (slightly unfavorable) review of the DDP here:
Disney World Dining Plan 2011 & 2012 Costs & Reviews - DisTouristBlog