Mebbid
Aquarium Advice Addict
Amazon, bulk reef supply, drs foster and smith, eBay, pet solutions, reefs 2 go(livestock), petco online(livestock in much better health than when you get them from most petco stores), reefcleaners, all are good sites that sell either livestock or supplies. I've always had good experience with these.
I would add Big Al's pets to that list. I have bought almost every piece of fish equipment I have from that site.