I enjoyed the stroll on Lincoln Road. I was there Sunday afternoon, and they had what I'd characterize as a "high class flea market" that closed at about 6:30. I bought some cufflinks from an estate jewelry guy. I'd also recommend buying a cigar or a couple of drinks and people watching. There is a restaurant called "Yuca" that has an upstairs (not affiliated) that offers salsa dancing classes on Sun, Weds, and Fri. $29.00 for about 2 hours of instruction and an hour of practice.

Later in the evening, Ocean Drive is good for people watching/barhopping. There is a public beach as well.

Please note that taxis are EXPENSIVE ($5.00/mile; $43.00 from MIA to Key Biscayne or $33 from MIA-South Beach) and not all of them take plastic. If that's an issue, ask when you call a cab and they will get one for you. They have to run your card by hand, and call it in....takes about 5 minutes to resolve. $5.00 does not sound like much, but MIA is surprisingly spread out.