monoprice.com is an amazing place to buy any type of cable. I have purchased hdmi, component, optical and coax from them.
I have not seen anywhere sell them close to what they do, and the quality is of the cables is really good.
I believe the warehouse is in Northern California, only took a few days for delivery.
I've also referred a few friends, one guy needed a fairly long hdmi cable, and he got it for like 15 bucks or something, dirt cheap compared to anywhere else.
If you need more convincing, browse
AVS Forum, they are very highly recommended there as well.