If you're open to the idea, I strongly urge you to adopt an adult dog (or at least adolescent). The training usually goes faster because the dog is older and less "puppy", including the potty training. Plus, you also usually miss out on the destructive chewing phase of teething. If it were me, I'd personally look into adopting an adult lab or lab cross, boxer or boxer cross, retriever/retriever cross, or poodle/poodle cross.
Yes, stay away from hounds. And yes, do go through obedience training with the dog so that the dog has good understanding and training to come/sit/stay/down.
This website has a lot good info, including a quiz you can take (be honest while taking it) to help narrow the field:
For medium size dogs, I like schnauzers, cocker spaniels (but be aware of genetic issues of aggressiveness in some lines), springer spaniel, medium poodle (I don't remember the name, but not the standard poodle and not the miniature poodle). If you'd like something a bit smaller, pugs, boston terriers, rat terriers, Jack Russell Terrier, etc (but are high energy) can be good, or the Cavalier King Charles Spaniel is an excellent companion dog.
We have 2 large dogs, and a small fenced yard (one is a GSD cross, the other is retriever and a bunch of other stuff). They were both 4/5 years old when our son was born, and we went through obedience training. Paying the money & putting in the time to do the training has been the best time/money we ever spent on them (other than vet care).