Not to many great ski shops in the Metro area any time of the year, as far as I know. Best ones that I know of are either Sno Haus location on L.I. in Hempstead, or further east in Huntington.
They carry a pretty good line of clothing, a fairly good stock of skis, and have a pretty knowledgeable staff but I'm not sure what they have left at this point. I wouldn't bother with Ski Stop in Plainview. Large store, but I'm not a fan due to employees that for the most part are completely clueless.