By Lenn Thompson, Executive Editor There is more chardonnay planted on Long Island than any other white grape, but those aren't the wines that excite me most — not by a long shot. If I had the money to buy and plant a vineyard right now, my white wine program would be heavy on sauvignon blanc. It's the white grape that shows the most consistent promise here, is one that winemakers are doing great things with today, and a grape that I expect even better things from in the future. For many years and through winemaking changes, I've enjoyed the…