Best Seasonal Menu right now for $30?
Presuming that $30 is for food only, it will cover the 3-course lunch prix-fixes at several upscale restaurants. In addition to DaveS's suggestion, here are a few other places to consider:
Fleur de Sel - $25 http://www.fleurdeselnyc.com
Gotham Bar & Grill - $27 http://www.gothambarandgrill.com
Tocqueville - $24.07 http://www.tocquevillerestaurant.com
Devi - $24.07 http://www.devinyc.com
Town - $26 http://www.townnyc.com/town.html