I don't have one (but I do have a greyhound mix) and I have heard they are real couch potatoes. They are supposed to be real sweet. The only thing is that you can't have them off leash in an open area (as in not fenced) because their chase drive is so strong they will run off and could easily get hurt.
I would look into a greyhound rescue. There are supposed to be some ex-raceing rescues. Good luck!