Some, but not all, of the above replies are misleading. There are no hard and fast rules regarding bi-wiring. The best advice I can offer is to listen carefully, without preconceptions. For some speaker/wire/amp combinations, bi-wiring is clearly the way to go. For other combinations it's a waste of money. For what it's worth, in my system I bi-wire and use double runs of cable.
Bi-wire cable versus 2 sets of cable
If I have an amp with 4 connectors (for bi-wiring) and speakers that are bi-wirable, do you get better quality sound with two separate speaker cables than you would with one set of speaker cables that are bi-wire (2 prongs on one end and 4 on the other end)? There would be a cost to two separate sets of wires, but is it worth it? Please help. Thanks, Scott