If you are looking for a really good reasonably-priced dinner, make you way to Osteria Enoteca on Fondamenta Rio Marin. It's located at Calle S. Zuane (at the bridge over Rio Marin). It was by far the best food we had in Venice. Hands down!
Unfortunately (or fortunately), this place doesn't show up on Google Maps or TripAdvisor. Very-very good! Give it a try, you won't be sorry.