Hottest Hotel Spas| forbes.com

It's pretty much conceded by industry professionals that the spa market is nearly mature. There aren't too many more consumers out there to convert, unless you count the men who will likely never be any more than occasional dabblers. But at the same time, more and more hotels are fine-tuning their spa services in response to increased guest demand. At least in the U.S., it seems, if you don't have a spa, you're not really a full-service hotel.