As your Roxy was a pittie, I think another - there are always available rescue dogs and pups - would be a great choice if your housing permits it! You already know about their energy level, etc., they don't shed a lot and would be fine being a city dog as long as they got enough exercise!

Of course, it will all depend the most on who tugs at your heart when you are ready, but I have a feeling a certain wrinkly-faced angel will be guiding that choice, regardless of breed!