There are rooftop bar-restaurants and then there's His Highness Leo, who will put you in the lap of the gods in the warmer months on the 8th floor of the Hotel Clark, with the Royal Palace above and the Danube below. Food (burgers, gyros, sausages, steak) is pricey but OK; try one of the sublime cocktails (from 2850Ft). Booking a must.
Leo Budapest
Top choice in Castle District