Best good ole' whiskey sour in Manhattan?
Schillers also does a Manhattan Sour. They add a splash of dry red wine to the top of the Whiskey Sour. VERY tasty.
Also try Balthazar. Properly made drinks including Whiskey Sours there. I strongly recommend the "Thomas". It's equal parts Honey and Lemon Juice, plus Ransom Old Tom Gin, and a splash of champagne. Whiskey Sour-esque flavors of Lemony Sweet Sour and Fizzy ! Oh and get the fries too.