Short answer: It depends.
If the purpose of adding the location to the domain name for the sake of adding it for "SEO," then I wouldn't do it. If it's an established business and has been around for a while, then I wouldn't recommend it.
If the business is new, and doesn't have a presence, then I would consider doing this. Again, it really depends on the branding for the business. If you add a city name to the business name, does it make sense, rhyme, or have a jingle to it? If it doesn't fit, then it doesn't fit.
Hope that helps.