I love all hounds, from Walkers to Blue Ticked Coon Hounds. They are medium sized , extremely smart, but more mellow. They like to track things though, so it's important they get walked alot and get to go find things. I also love pointers (German wirehaired pointer). They are more athletic though, so definitely need to be run regularly. For small dogs, I love wirehaired Jack Russells, but they are extremely energetic and need tons of energy releasing excercise. In fact a lot of small dogs have more requirements for vigorous excercise.
But seriously, I recommend adopting a mutt from the SPCA. There are so many dogs put to sleep every year that would have made a lovig pet, and mixed breed dogs have great temperament and usually more resistant to arthritis and defects from purebreds (aka inbreds). Ever wonder why labs, shephards, and retrievers all seem to get hip dysplasia? or why pugs and sharpeis are so prone to skin infections? inbreeding baby, inbreeding.
You can also get purebreds through a rescue center, rather than a breeder. This is a great option if you would like to save a life and still have a pedigreed dog.