I'm in Paris at the moment, staying in the 9th arrondissement which is great but for the sake of half a mile or so out of town I think the next time we'll stay in Montmartre. Where we are is good - bustling, loads of bars/food etc but Montmartre just has a more relaxed vibe, like a village but still typically Parisien.
Overall, amazing city. One of my favourites.