I'd second Javeryh's comment.
Try and zero in on a particular theme or element you really like, then play that up. To me, that's when the artwork starts to get interesting.
Where's the cab going, a gameroom?, the Living Room?, is there a pool table, bar, etc.
Maybe you already have some art you could tie into, or specific colors in the carpet, walls, etc?
If you can get a specific theme in mind, do a google images search for those keywords. That'll result in all kinds of ideas! I spent hours digging through the results of "steampunk gears"