What are your "go to" quick service restaurants in each of the Disney Parks? The ones that even when you don't know what you want to eat you know you can go and get a decent meal.
I think these are mine...
Magic Kingdom - Pecos Bills
Animal Kingdom - Yak & Yeti
Epcot - Sunshine Seasons
Hollywood Studios - I don't have one here 
Magic Kingdom - Columbia Harbour House
Epcot- Cantina
Cosmic Ray's in Magic Kingdom is the only one I can think of. Although I do tend to end up at ABC Commissary in Hollywood Studios simply because I want the chocolate mousse.
Magic Kingdom - Pecos Bills or Casey's Corner
Animal Kingdom - Flametree BBQ
Epcot - Tangerine Cafe
Hollywood Studios - I don't think I've ever done a quick service there
At Epcot, if I don't have a reservation and want a good meal I go to Restaurant Marrakesh first. It's almost always possible to get in there without an ADR. But if, wonder of wonders, they were also full, I couldn't pick just one counter-service place. There are so many interesting choices at Epcot.
As for the other parks...
Magic Kingdom - Columbia Harbor House
Hollywood Studios - ABC Commissary
Animal Kingdom - Yak and Yeti counter service
Ours would probably be:
Magic Kingdom - Pecos Bills or Columbia Harbor House
Animal Kingdom - Yak & Yeti
Epcot - Sunshine Seasons
Hollywood Studios - The Back Lot Express
Scrappy may argue the point!
My hubby and I usually only do one sit down dining a day. We usually like to get filling sandwiches or treats that keep us going through out the day and we can walk around and eat them. That way we don't miss a minute of the Disney fun. Then we eat dinner at the hotel at night.
Magic Kingdom: Sleepy Hollow~ Love their funnel cakes and ice cream cookie sandwich.
Hollywood Studios: The pretzel kiosk beside the Great Movie Ride(they have awesome stuffed pretzels. Both the jalapeno and cream cheese and the cinnamon and cream cheese taste great!
Epcot: Les Halles Boulangerie & Patisserie~ Their baguette and croissant sandwiches are delicious and very reasonably priced.
We don't usually eat when we are at animal kingdom. I think we'll try Yak & Yeti someday though since everyone seems to like it.
Epcot - Sunshine Seasons
Magic Kingdom - Pecos Bills
Hollywood Studios - The Back Lot Express
Animal Kingdom - Flame Tree BBQ
Mine are as follows:
MK Cosmic Ray's
EP Sunshine seasons
AK Flame Tree BBQ
HS ABC Commisary or The Back Lot Express.
MK- Pecos Bills or Cosmic Rays
AK- Pizzafari. We are going to try Flame Tree BBQ in November and maybe Yak and Yeti
Epcot- Sunshine Seasons
HS- Pizza Planet. I do LOVE my pizza 
MK: Pecos Bill
Epcot: Yorkshire County Fish Shop
AK: Harambe Market snack cart for jalapeno cheese pretzels. 2 of them and a Safari Amber make a delightful meal!
HS: Pizza Planet. Same pizza you get everywhere else, but it tastes better surrounded by Toy Story!
MK: Cosmic Rays
AK: Flame Tree BBQ
Ep: Tangerine cafe
HS: Starring roles
Epcot- Electric Umbrella or Sunshine Seasons
MK- Casey's Corner, Cosmic Rays or Pecos Bills
AK- Restaurantosaurus
DHS- Backlot Express