Australian Shepherd
Credit: Hans Surfer / Getty Images

Best for: Those inclined toward a truly constant companion (or it'll go crazy) that craves order (or it'll panic) and affection (or it'll be sad).

Left alone with nothing to do, this lively working dog will turn your couch into a chew toy. Left with kids, it'll try to herd them. But for active types with attention to give (and an arsenal of lint rollers – these guys shed), the Aussie is ideal. Bonus points for its unusual splotchy coat, multicolored peepers, and nickname: ghost-eye dog.