Favorites:

El Gaucho:
Argentine steak house. Not terribly expensive. The Gaucho steak is incredible and one of the best cuts I have ever tried.

Flying Fishbone:
Upscale cuisine in a casual atmosphere right on the beach. Pricey but worth it. Phenomenal ambiance.

Madame Jeanette's:
Casual European (Austrian/German) and American fusion cuisine. Massive quantities of very good food.

Aqua Grill:
Seafood grilled on a wood fire. Very good food in a nice upscale atmosphere.

Amazonia/Texas de Brazil:
Brazillian chuascarria (steakhouse). If you have never been to one you need to try this once. They bring various cuts of grilled meat right to your table.

Matilde:
Pretty good French cuisine. Upscale but somewhat pricey.

Iguana Joe's:
Hands-down the best place to grab an appetizer and a drink and people-watch downtown.

Enjoy!!