Personally, I'm a huge fan of tile as a substrate. Individual tiles are very easy to clean, and periodically, I'll just take them all out and give them a good scrub-down.
Figuring out the size and quantity of tiles can be tricky, though. You want as little space between tiles as possible, and you want to make sure that they all lie flat on the bottom of the tank. If any of them are raised, crickets will find their way under the tiles and just die and rot. In addition, tiles are rarely uniform in size. If you go with multi-colored tiles, you can almost guarantee that they won't be the same sizes. I would almost recommend bringing in the tank to the hardware store and making sure they all fit in flat with little space between them before you make the call. Lowe's will cut tile to your specifications. I haven't found any other hardware stores that do. Also, go with non-laminated (rough) tiles. It's a more natural environment and it gives them something to grip.
I also use a rubber shelf mat underneath the tiles. This helps make sure you aren't banging the tiles against the glass tank and prevents damage, and also works well to keep any feces or other hard-to-remove substances off the glass of the tank itself. That way, if it gets really messy, you can just throw out the rubber mat and get a new one. You can usually find this material in rolls in the shelving/storage department of a home improvement store and it's relatively cheap.
Good luck.