The best LI wines I've had were from Macari.
I haven't had, but Paumanok Vineyards has very strong rep.
The owners at Old Field (Ros and Chris Baiz) are friends of mine. Until
recently they were unusual in making a good Pinot, but ask if they
still have the '97 Pinot Reserve.
http://www.theoldfield.com/
I've had good wines from Lenz, but spottier. Spottier still is
Pelligrini.
HTH!