Before I read this article, I assumed that small dogs would make the best dogs for apartment living, but size is not the main factor to look at when deciding on an apartment friendly dog. The most important characteristics are the energy level of the dog and the dogs barking habits. Apartment dogs should be more laid back, need little to moderate exercise, and do little barking.
If you live in an apartment or small dwelling space, take a look at this article for the best breed for you.
13 Apartment Friendly Dog Breeds: http://www.vetstreet.com/dogs/13-dog-breeds-ideal-for-apartments?Wt.mc_id=facebook&WT.mc_id=ETA