I could see an apartment building being a fine addition. The main floor would be a lobby. The 3 ground level extensions would be apartments. Each one's furniture would reflect the personality of those living there (though keep in mind the wallpaper/flooring should be the same because apartments don't let you change that). The basement could be a maintenance and storage area. The top floor could be a penthouse, which would be a lot fancier than the other apartments.
Also, try to figure out what your city's main industries are. After all, cities don't just pop up in random locations. There has to be a reason that location is better than others. Is your city located near a port that has particularly good sea access? Is it near some natural resource? There can definitely be multiple reasons for this. Whatever this happens to be, it could play into what you end up building.