The centerpiece was something I'd bought from shorpy.com, which I'd discovered on the recommendation of a forum regular on Old House Web. It's a shot of a freezing cold, February day in Brooklyn Heights circa 1908 with the Manhattan Bridge under construction in the distance. The detail on the photo was mesmerizing (click here to see what I mean).
I bought a large copy of it. My intent was to frame it myself. After all, if I can construct cabinets and stained glass, how difficult could it be? However, as I started researching the techniques online I kept seeing comments recommending a web site, http://www.customframesolutions.com/, which would build the frames for you for about the same price as stick building them. You provide the dimensions and they ship it to you in two to four business days. I priced out a nice frame, matte and foam board for around a hundred bucks. Pretty good deal.