We used to have muscovies and mallard in the garden when I was a kid. We had quite a big pond. I suspect that if we hadn't had a pond the mallard would have flown off to look for one. They're fairly wild by nature. But the muscovies don't fly a lot - too bloody fat and lazy, and very sociable. They were always nipping into the house to steal cat food. Whatever breed you get, put it in a pen and feed it lots for a week or so until it gets used to you being an easy source of food. Then you can let it out and it will probably stick around.
My Dad was a very keen gardener so he used to fence off the pond area to stop the muscovies walking into the flower beds to trash them, which they loved to do. He stopped them flying over the fence by catching them in the spring and clipping their wing feathers. But this made them a bit vulnerable to Mr Fox.
If you're only going to have one duck you should be able to tame it by buying it in the egg. Stick it in the airing cupboard and it will think you are its mummy when it hatches. Then it will follow you everywhere, beeping frantically. You'll need to keep it out of carpeted rooms and be fairly handy with a damp cloth because you can't train it to use a litter tray. For a while we had muscovy ducklings and dalmatian puppies in the kitchen and they all got on rather well and insisted on eating each other's food.
We ate one of our muscovies, and it was fairly rank. Probably too old. A duckling would have been much juicier, but I defy anyone to kill their own duckling.
Edit: if you do have a pet duck in the house it will be a bit vulnerable to nasty children e.g. my little brother who decided to teach Henry to swim by putting him in the lavatory and flushing it. After that he limped a bit so was rechristened Hopalong Henry.
