This store is located in a a basement on 45th street. I'm 33 and since I was a kid of 1 or so, I've made the pilgrimage to this store (or at least it's ancestors located in the same space) and have always been able to find the best selection of scale models and supplies outside of a mail order catalog. I recently visited the store after having not been there in many, many years. While they didn't have the specific model I wanted, the place is still an obvious haven for the serious scale modelling hobbyist and train hobbyist (not my bag, but I can see by the looks of the place...) Be forewarned though, it can get quite stuffy down there in the summer months.
Pros: selection, supplies, sorted by scale
Cons: hard to find, small/crowded, hot in summer