I''ve ordered nice chains from Rio Grande, they have 14 and 18k gold, and very nice styles. Their prices are pretty reasonable, I think. Hope that helps.
I bought a couple of chains from gemologica.com they also have an ebay store, but it was cheaper to go through their site directly plus they gave a discount. My chains were just simple rope chains.
I have gotten superb service from goldspeed.com and think that is is always worth taking a look at their website if one is looking for a chain. I am not sure that they will always have the best price, but they have decent prices; a good selection; and are very professional. When UPS failed to make a delivery to me after three attempts, they offered me my money back or offered to make another delivery attempt for $8.50. I wrote to them, saying that I would like my money back because I did not want to pay twice for delivery, and they waived the delivery fee.