Table service - you can normally order what you want with a few restrictions in some places.
There are masses of places in the parks where you can get your counter service meals.
You can use your vouchers for character meals in all parks and resorts - book well in advance!
We were on the dining plan last year and hardly bought any extra meals - portions are huge so most days we only ate 2 x a day. We didn't have any kids with us though.
Am sure there are lots of threads on here about this - try searching for dining plan?
allears.net has masses of information, profiles, menus and even recipes.
Hope that helps a bit.
oh and by the way, welcome! Am sure you will have fun and find lots of info here.