Florida: Jupiter Island
Median home value: $4,437,400
Median household income: $250,001
This tiny channel island is a 17-mile-long private island with just over 800 residents. Though the location is low-key and off the radar, its properties are anything but — Celine Dion owned a $72.5 million mansion with its own water park here and Tiger Woods’ estate has a 4-green golf course, 100-foot lap pool, 60-foot diving pool and a spa.