I've read exactly one semi-scientific comparison of popular DVI cables of varying price. Amazingly, the conclusion was that Monster Cables really are better. However the difference had no effect unless you were running a high-bandwidth signal (>=1920x1080x60Hz) over a long distance (>=12 feet? I don't recall exactly). The cheaper long cables would work for low bandwidth signals, but would lose sync and fail at high rez.

Either way: monoprice.com