As mentioned, make the decor fit the place. Beach and maritime themed decorations if near the ocean, moutainy stuff in the mountains, spurs and horse shoes in the southwest/desert, etc. At fineartamerica.com it's easy to search for prints by location, so you can feature skyline or local landmark photos. I like Acrylic prints because they not only look great, but they take the hassle out of finding a frame and are easy to hang and clean.
I have an STR that will be going public in the next few weeks in Greenville SC that has a rich industrial textile history, and the house is very close to one of the newly renovated mills and a secondary/mini downtown area. From Etsy and Ebay I bought some old gears, a large socket, pressure gauge, and other old industrial stuff that I will place on walls and on floating shelves, in addition to the types of prints I mentioned above. None of my competition seems to theme nearly as much and their calendars faired OK in the late fall/early winter months, so I think I'll do alright . . . . Time will tell!