First, check on the different varieties of the meal plan they have available... Regular (1 sit down/character, 1 counter, one snack per day per person), Delux (3 meals your choice/2 snacks $70/$20). Determine if the $40ish/day per adult (only $10/day for kids under 10) is more or less than you'd normally spend on your dining. I'd go from there. If you're definately going to go to a character meal or a sit down almost every day that's worth $30+ and get something quick to go (plus you mentioned grabbing snacks around EPCOT) it is probably worth it.
Jan '07 Pop Century, Mar '07 Day Trip, April '07 Off Property, May '07 OKW, July '07 POR, Oct '07 Pop Century (& MNSSHP!!!), Dec '07 Day Trip
Jan '08 POR
Feb '08 Pop
Mar '08 Off Property
April '08 AS Sports - I think - still gotta book it