Looking for a laid back breed

greyhounds can be giant couch slugs.If you let them run once in a while, they will reward you with plenty of down time (or so I keep hearing)

Ditto Tylers mom.....rescue a retired greyhound.

or a bluetick coonhound -- check out the "I'm conducting an experiment thread" LOL! My 3.5 year old spent 16.5 hours on the couch with one pee break.   But then he's tons of fun out of doors - rafting, hiking, road trips, etc.

Laid back = Saint Bernard
 
Many of the giant breeds are LAZY. Mine spend a huge amount of their day on the couch [] I like that when I get home from work they greet me, then return to their sleeping spots while I unwind. (Of course if they see a leash or sense that I may be taking them for a W-A-L-K, it suddenly becomes a rodeo of with excited Saints leaping through the air. But the excitement is short lived, and they calm down once we get out the door.)
 
If you have the space inside your house (a saint sprawled at your feet in the bathroom can be tricky to work around)  a large vehicle to transport your dogs, and do not mind slobber and buying large amounts of dogfood, they are wonderful dogs! I think that the sweet nature of Saints, along with their absolute willingness to lay at my feet sleeping for hours on end out-weighs some of the inconviences of dealing with giant dogs.
 
 

Definitely AVOID herding breeds (Collie, Aussie, Sheltie, Corgi, English Shepherd, etc.) if you are looking for laid back.  They are active dogs.

Kayla had a lot of whippet in her .... so I would go with either greyhound or whippet.  They are the sweetest things!  Just like to be by you and be wam.

I second the hound dogs. My girlfriend had a laid back rescue greyhound, a wonderful dog. I have had bloodhounds, and I've known basset hounds. And those EARS on most scent hounds, you'll never see anything cuter than a bloodhound puppy. It was almost impossible to walk mine down the street when he was a pup. (Sadly, he died of bloat two years later.)

I have a hound, too - couch potato indoors, but will trot nicely beside you for miles!  I would avoid Beagles - they are cute, but can be busy.  The larger hounds bred to hunt fox, raccoon or coyote are usually the more mellow fellows.  Blue ticks, red ticks, foxhounds, and redbone coonhounds (these are probably the quietest of the hounds).  Do NOT get a Plotthound unless you like noise.
Avoid herders & hunters & bird dogs if you want mellow.
An English style Lab (blocky head, stocky short build) might be OK, but avoid the field types (tall & lean).  Maybe a laid back rescued Golden Retriever if you don't mind shedding.
Stay away from terriers for the most part.  They tend to be active, too.
 

While I don't have experience myself with them, I have heard many people say retired greyhounds are wonderfully calm pets.  Whenever I see someone with a greyhound, I always ask if the dog is a couch pototo like I've heard before.  Inevitably, the person says, "Oh yes!"  I've also heard they like to cuddle (must be a need for warmth since they're short haired and so slender).  I think they're just so happy not to have to race anymore that they are thrilled to just kick back and relax!

Pass on the terriers!  they are high energy and loooove to play. How about a Golden?

I vote for the greyhound also!  My friend had a retired racer and she was a huge couch-potatoe.  I house sat for her one time and brought Nigel with me....they got along wonderfully and it was really amusing to watch them play chase!!!  Nigel tried and tried to catch her, but he never could, finally he just stood in the middle of the yard and tried to get her when she went past!!!  They tired each other out!!!

Max is a GSD/lab X and he's about as laid back a mutt as you'll find anywhere.  He loves his walks and his trips to the dog park, but he's also content to move from couch to bed to couch to carpet and spend most of the day snoozing. He doesn't bark, even when someone comes into the yard or rings the doorbell [] but he has been known to grab a squeaky toy and *bark & squeak* all through the "Sopranos".

Joyce & Max

like everyone said, a retired greyhound is a good choice.  I know a lot of people are not fond of poodles, but my standard is VERY inactive indoors.  Indoors=couch.  Outside he loves to play and have fun.... but once we come back home its nap time
 

I'm gonna take a different tack here -- rather than 'breed' I'm gonna suggest "mature".  NOT a puppy.   In fact, try a dog over 3.  Still in the prime of life, but often incredibly 'thankful' to have a good home.  Try breed rescue if you want to know 'more' about the dog -- but please consider an older/mature dog. 
 
Some of the most wonderful dogs I've had have been mature dogs.  Sometimes, yes, they may have issues,but what puppy on the planet doesn't have 'issues' with housetraining, chewing, exercise and brainlessness in general??
 
When you go with a mature dog you often find they're ready when you are, but not just mindlessly active. 
 
Just had to say a word for my favorites -- the "old guys" and the grow-up dogs who so BADLY need a home.  Often too, you will know how the dog reacts to other dogs, children, prey, etc -- BEFORE you adopt.  See if they will let you foster for a while and make sure it's a fit.