Chris,
As I mentioned in my RS485 post, I'm using shielded twisted pair wire, and the maximum run is about ten feet. I tested it with a length of wire that was 100 feet long and it worked fine, but only tested as point-to-point with a total of two MAX485s. But when you actually start connecting multiple MAX485 modules off of the main bus, things can get interesting. Because the bypass capacitors that I mentioned were what finally fixed the last of my problems, it's possible that you could use just about any wire and it would work fine -- I don't know if non-twisted non-shielded wire was ever part of my problem, considering how close my modules are to each other.
Randy