Our dogs aren't allowed on the furniture either.
Angus, he has a few favorite spots, but I think his 2 favorites are in front of either Marks chair or mine (& it is a big pain to try & get in your chair with a 120 lb dog laying in front of it!).
And Roxey, hers is laying in front of the couch. That's where she is 90% of the time when she's in the house.
And Huney, her favorite spot is laying in front of the front door, she even sleeps there at night. She was never taught this, it's just where she feels comfortable.