I've been basing most of my miniatures lately with a gray stone floor motif, with the intention of doing some games in a dungeon environment. With that in mind I've started considering options for surfaces. For the moment I've ditched the idea of anything commercially made. Professionally made products are stunning in their appearance, but cost more than I'm currently inclined to spend.
I've experimented a bit with paper tiles, and paper may be the way I eventually go. I also spotted an idea on the terragenesis site for using foam core to make paved floors. The specific method I tested was devised by a contributor there named Ariss, and the process basically goes like this:
1. Peel the paper off one side of the foam core.
2. Draw lines with a stylus-like instrument of some sort to make gaps between the individual paving slabs.
3. Paint (I used a simple base coat of black, followed by a coat of medium gray -- intentionally not getting it into every single nook and cranny -- followed by a dry brushing of light gray).
I tested it on a small 6" x 6" area just to see how it would work out.
I prefer the foam core floor to a paper terrain floor, since I'm also planning to make other pieces (walls, pillars, stairs leading to elevated surfaces, etc.) out of styrofoam packing materials as well. With a foam core floor, all my pieces will be made of the same material and painted the same way, thereby looking like they're all part of the same stone structure. They also have the advantage of actually being 3D, rather than 3D illusions printed onto a 2D surface.
I haven't decided yet whether to do a single large floor area (something like a full sheet of foam core in size), or various 12" x 12" modular pieces. Each has its advantages, I think. Of course, these are quick enough to crank out I could just do both and see how it goes.