By Lenn Thompson, Editor-in-Chief As I mentioned last week, there really are some terrific values to be had on Long Island — even in the $15 range. For the most part, Long Island's best $15 wines are chardonnay based and are fermented either mostly or entirely in steel. That's because there's a lot of chardonnay grown here (it's the second most-planted grape after merlot) and by eschewing oak barrels, winemakers can keep their costs down significantly. Paumanok Vineyards can always be counted on for at least two value wines, their "Festival" labels, which include a red blend and a chardonnay.…