I've seen some less-than-honest companies with BBB seals, and know of some internet companies who have really poor BBB reps but don't seem to do anything to clean up their act - so I've learned not to place too much trust in those things.

My first job out of college was working in the QA department for a company undergoing ISO 9000 certification. The most important lesson I took away from that was that with the right paperwork and the proper wording, just about any company can get just about any certification. Whenever I'm researching a company, I speak to friends and acquaintances who have used the service. The feedback I receive from sources *I* trust will help me make my decision.