If you want to go to any of the above....Mexico, China or Italy, I strongly recommend a reservation. Just walking in and expecting to be seated is not a good idea and you will be disappointed. You will waste precious time waiting for a table.
I would also make reservations at any of the hotel restaurants that you want to go to especially those at the deluxe hotels. They are impossible to get into without a reservation.
If you are staying at a value resort, I would not waste my time going back to the hotel for a counter service meal...and that's what you will get. Values do not have table service restaurants. You can get the same food at a counter service in the park.
Do be sure, since it is just you and your husband, to explore the restaurants at the monorail hotels. The Kona Cafe in the Polynesian is wonderful for breakfast. You will have to take a bus to TTC and then the monorail to the Poly but it is worth the trip.
The Grand Floridian Cafe is also wonderful for breakfast.....I would make reservations at both. You can chance a walk in but why. Just give yourself an hour for transportation.
Now....on to the subject of The Disney Dining Plan (DDP)....... if it is free with your vacation package, it is a no brainer to take it. However, if you need to pay for it, there are those on this board who have done the math and feel that it is not with the money. You would have to figure that our for yourself depending on your dietary needs and habit.
So.....Disney Dining Plan.......... Disney Dining Reservations...... 2 different things.
Reservations are a must at almost table service restaurants especially those at Epcot or deluxe hotels......
Disney Dining Plan an option.....if it is free....take it.....
If you have to pay for it....you do the math.
Have a Magical Trip!