okay...let's see if I can pick a couple in each park:
MK - I have a couple here: the benches that, true, are in the smoking section near Space Mountain...you can watch the Astro Orbiters ahead, the Carousel of Progress is nearby, the TTA is chugging ahead...it's certainly not a quiet place, but it's one of my favorites to sit and just soak up the atmosphere.
in Adventureland, find some benches between Swiss Family Treehouse and Aloha Isle...you are out of the way and you can sit and enjoy your Dole Whip!
Ak - As you enter Africa and you see Tusker House to your left, you'll see another building to your right. (I think this may be a bathroom and a store) You'll find benches and tables and chairs back behind the building to the right and it's somewhat secluded back there (and shaded). EDIT: This was also a great quiet place if you needed to make a phone-call/check your voice mail while in the park I found!
I also like...along the river, there was a sitting place as you are heading into Asia (just before you get to the coffee shop/bagel/danish place the name of which escapes me at the moment). Sit there on the right with the river beneath you and you'll see a boat filled with coca-cola (or at least boxes labeled coca-cola). It's right behind the building covered in Coke signs. Very relaxing and quiet here. I've picked this spot to enjoy my juice and bagel after riding Everest in the morning (before my morning Safari).
Epcot - I agree on the choice of the UK gardens. Very relaxing. It's one of my favorite picture spots...but you can also enjoy either fish/chips/ale or cadbury chocolate here!
I also like going all the way back into Morocco where the restaurant entrance is. If you sit here, you can't see/hear the bustle of the rest of the park so much and you can believe you truly are in a foreign place...! If you sit for a few minutes, you may just be lucky enough to find Aladdin, Jasmine or Genie (or some combination of them).
MGM - Wow! This is a toughie for some reason. Maybe we don't stop rushing around in this park (or we sit enough 'cause most of the attractions are shows?). I honestly can't think of anywhere.
Oh what we do for our fellow Disers
