I have searched the web for some affordable speaker cables. While I haven't tried any yet, here are the best prices and web-sites I've found for what I would consider to be "good" cables:

DIY - 12 gauge (spades or plugs) 8 ft pair $40
Straight Wire Rhythm 8 ft pair $48 (spade) www.audioadvisor.com
AudioQuest Type 4 8 ft pair $70 (spade) www.audioadvisor.com
Kimber Kable 4PR 8 ft pair $70 (spade) www.audioadvisor.com
Straight Wire Stage 8 ft pair $84 (spade) www.audioadvisor.com
T-14 Silver Sonic 8 ft pair $90 (spade) www.anchoraud.com/default.htm
T-14 Silver Sonic 8 ft pair $95 (spade) www.audioc.com
T-14 Silver Sonic 8 ft pair $105 (banana) www.audioc.com
AudioQuest Type 4 8 ft pair $90 (banana) www.audioadvisor.com