Equinox (same hotel / dining area as Jaan) has a gorgeous view. Food's cheaper than Jaan so within your budget, but of course not as good. Oh, they charge s$20 for a table by the window. And they don't serve free water, gotta pay s$5/pax for 'filtered water.'

Ocean Restaurant is pretty unique in that it's next to the large tank in RWS's aquarium. No clue about the food or service though as I haven't visited.

If you're looking for something a little more 'green,' Corner House is in a colonial building in the middle of SG's Botanic Gardens.