BF and I find ourselves wanting to get away for a week or so in September. Where would you say we go?

Requirements:

• Easy to get to from NYC
• Not terribly expensive
• Good mix of things to do - whether sitting around on a beach or sightseeing
• Interesting things to do

Ideas we've had so far in this vein:

• Iceland
• Amsterdam/Netherlands
• Buenos Aires (long flight, but still just one flight)
• Hawaii
• Cruise up the Atlantic into Nova Scotia
• Costa Rica

What do people recommend?