When large dogs eliminate, they eliminate a lot more than small dogs. More goes in and more comes out of large breeds. Which is something to keep in mind if your dog will live inside - especially if you live in a high rise apartment and he will have to be litter box trained (there is always going to be more to clean up).
Your dogs temperament should match yours. Do not choose a breed that is highly energetic if you are a couch potato. On the other hand, if you want a dog that will follow you everywhere around the house and who is always ready for a game of fetch or tug of war then you should consider a dog that is highly active and always has a lot of energy, instead of one of the lethargic breeds.
The following list uses a wide interpretation of "breed." Breeds are usually categorized by the functional type from which the breed was developed. The basic types are companion dogs, guard dogs, hunting dogs, herding dogs, and working dogs, although there are many other types and subtypes. Breeds listed here may be traditional breeds with long histories as registered breeds, rare breeds with their own registries, or new breeds that may still be under development.
Every breed can be trained to learn almost every command. However, some breeds learn a lot faster than others - making them a lot easier to train. These highly intelligent breeds pick up a command after only about five or six repetitions, they more often respond on the first time you give the command, and they remember commands even if they are not practiced often. They also learn commands even when the trainer is inexperienced and makes mistakes. So if you do not have a lot of the time to spend dog training, or you are the impatient type who gets frustrated easily, choose a breed which has a high ease of training rating.