Bazaar
Med food is eaten in the Gothic brick-lined cellar below (to the tune of a tinkling pianist). The rooftop, with its view of the castle, is the place to see and be-seen.
Address: Nerudova 40, tel.: +420.257.53.50.50
http://www.restaurantbazaar.cz/

Kajetanka
Have a drink here when you are visiting the Prague Castle...it offers an excellent view over the the town.
Address: At the end of the long stairs up to the castle in the street Zamecke Schody.
(no website yet)

Klub Lávka
The terrace of this club is situated directely at the Moldau-river in front of the Smetana museum. Take a sip of your wine and enjoye the evening sun!
Address: Novotného lávka 1, tel.: +420.222.222.156
http://www.lavka.cz/

Zofin
If you need a break walking along the Vltava river, why not stop at the Strelecký Ostrov...a small green island in the river. And while you are there, take a bite or drink at this nice restaurant.
Address: you can't miss it on this island
(no website yet)