Mara -- 12 year old Border Collie / German Shepherd mix. She was a pound puppy, adopted (and probably abused), then returned to the humane society. She was my 10th birthday present, the only dog at the humane society that didn't bark or whine when we passed her kennel. Of course she turned out to be completely nuts -- typical herding dog, but didn't respond to training, bit people and fought other dogs, etc. She's since settled down and I wouldn't be surprised if she's still alive when I finish my master's degree .
Docker -- 4 year old Golden. The most expensive dog we've ever bought, probably also the least intelligent. Someone recently guessed his age at 6 months... We still love him though.