Like the others mentioned, yes those breeds sound wonderful for you. But since you are aware that you are going to the shelter and that it will probably be a mixed breed I would just go from there. BC's are known to be barkers and are very hyper and need a job but if you can provide the excersize and training they are great dogs! I do rescue work, am a vet tech and volunter at 2 local shelters as well as all my dogs are all rescued from shelters so I will tell you my outlook on adopting a shelter dog. Take a couple visits to your local shelter(s) and look for what you want. Since you want to train it easily I would look for one about a 1 1/2 years or younger. You want one that is medium size so if you get one around 8 months or older it probably won't be much bigger than what it is now. If you choose a pup then ask the staff what breed(s) are mixed with it and look at the pups figure (the bigger the feet the bigger the dog ussually) the staff should be able to give an approx. size. Since you want a house dog that is quiet and easy to train look for one that does not eliminate in his run this ussually indicates a clean possibly house trained dog or at least easy to house train. Also look for one that does not bark excessivly (they will ussually be more excited when you enter the area than what they would be like once they settle in a home). Look for one that comes to the cage to see you, one that hovers in the back corner is a timid dog, sometimes with fear or other aggression behaviors. But a dog that is over excited (like jumping and barking like crazy) might be a little too hyper to train fast. Look for one that will let you touch his ears, feet and muzzle. Also remember the grooming involved, if you don't mind brushing everyday and a lot of shedding then a longer haired breed would be ok otherwise a shorter haired one would be better (although some short haired breeds also shed like mad). Also dogs with wrinkly skin require more cleaning as the folds of skin should be wiped clean often, a breed with a short muzzle might have problems in very hot weather and with lots of excersize. Look for one that has no obvious health issues like runny eyes, a limp, missing hair etc... Once you have a dog in mind visit with it a couple times, take it for a short walk and the shelter should have a special room and area outside for you to be with the dog away from other distractions so you will be able to see a little as to how the dog will react to you. Now don't be dissapointed as most dogs are so excited to be out of that little cage they have been stuck in for who knows how long so they will be a little more excited and may want to explore the area they are in a little more than explore you. NEVER be afraid to ask questions no matter how dumb they may seem as the only dumb questions are the ones that are never asked.

a BIG hooray for choosing to save a life and the best of luck to you and your new friend!!!