The restaurant at Topkapi Museum for the view - ask for the end seats outside.

The restaurant on the veranda of the Cirigan Palace Hotel - again, sit outside - spectacular view, walk the grounds at night - incredibly beautiful. Reasonable prices for that nice of a restaurant. Don't get sucked into bar that hangs out over the Bosphorus - somethig like a $25 cover charge (that was 3 years ago) & outrageously expensive drinks. (But it is pretty cool sitting there before you get the bill... )