Nature's Best Fish on RT 26S in Vestal is where I go most often. Their selection isn't that great, and their prices are a shade on the high side... but everything is healty and reliable. It's a small shop, the owner runs the place and is generally knowledgable - not a "salesman" either. Creature Comforts in Binghamton is OK. Much better selection, much better prices, but I've had terrible luck with their livestock - rarely healthy enough to last more than a couple of days in my tanks. The employees don't really know much, and the few that do will sell you whatever they can, regardless of whether or not your can/should have it in your tank.
Where are you from? I found a guy that lives in Owego with a 680g reef tank. If I can find a few more people, might be worth getting together to swap ideas, info, and maybe some frags depending on what people have.