Montys is great but it is just a bar, if you want more try BLT at the Betsy Hotel.

http://joesstonecrab.com/

Hands down best in Stone Crab in South Beach.

Tip: order take out, and eat it on the beach to avoid the wait.
Or, you have to know who and how much to bribe to get a table quickly.

Grillfish is a great option for fresh seafood and steaks.

Havana 1957 is a good Cuban place.

The Front Porch is a great breakfast spot.