Where should I move to in Miami, FL?

My girlfriend and I are wanting to move to a fun, nice area in Miami, FL but not too sure where to start our search. She is 27 and I am 31 (currently live in Scottsdale AZ) and we both love the ocean, exciting downtown energy, close areas for nightlife fun, and CLEAN. We want to live in a highrise condo also. I've seen many amazing condos on www.condos.com but I don't know which neighborhoods are good.