Another vote for cafe gray at the upper house. Great views, enjoyed the food, not cheap but for a special occasion I think it's worth it.
I Found Cafe Gray a bit "too much" personally.
I like it for a drink but I find the food average for the price I have paid.
But since food is not the main criteria....
You could also go french with Petrus at the Shangri La or Caprice at the 4 Seasons.
Had a lovely meal with a great view at the ToTTs in the Excelsior. But we were in a big group and were given the best table by the window.
The thing I find in hotel restaurants is there can be a total lack of ambience...?
is Red still going at the IFC? or Isolas?
if it's budget you are after there's the "pub" above the Disco bay ferry..
its cooler now so outdoors is possible..