I feel lucky. My LFS
is a Petco, of all things, but is probably the best fish store I have ever seen. They will refuse a sale if they don't think your tank is ready (though I'm sure a threat to call corporate could force their hands), and will always offer detailed advice on set up, compatibility, etc.
I actually watched the main fish guy turn away someone who was ready to drop a couple hundred on fish in a single trip, just because the tank was probably not finished cycling. He did tell him that if he brought in a water sample, and the cycle was done, he'd sell him a few to start off.