If you enjoy lots of sitdown meals with some beer or wine, and maybe not always with an appetizer and/or dessert, it may be better to get the Tables in Wonderland discount versus a dining plan.
If you think you'll be going back within a year, get the annual pass with the DVC discount. Even if you think you'll be going back EXACTLY in a year, just roll that vacation back one week and your tickets are paid for.
Other than that, "Bang for the buck" is in the eyes of the beholder, without knowing what you like to do on vacation, or if you just want to hit the parks as much as possible every day, the DVC membership itself might be good on its own.
Where you staying?