What breed of dog should I be looking into to get?

Yes, I've already asked this question but I'll ask again - I may have changed my mind a little, I don't know. Anyway, I live in a medium-sized house with a good enough sized backyard. I have one dog at this moment (a Chihuahua rescue) and I have a rabbit. I am looking for a dog that would be friendly and sociable (I know that depends on the training though) and an eager to please dog. Small, medium, big - it doesn't matter. I just want a friendly and lovable dog. I'd be training the dog as a puppy if that affects anything. I'd prefer a little bit more of an active dog than my Chihuahua because he has absolutely no interest in playing fetch or w/ a tennis ball and I'd like a dog that would do that. This would be my second dog =) All suggestions are welcome!