I've had the privilege of staying at a lot of amazing hotels. Hands down, The Mandarin Oriental in Chiang Mai is by far the most impressive and coolest hotel. You need a map to find your way around the property. And, to get around the property guests ride on "buggies", or golf carts. All the architecture takes you back in time (the property was built from ground up just six years ago). It mixes traditional/historical Thai and French Colonial architecture.
Here is a slideshow of pictures from the property:
Here are a couple videos of our villa:
Here is a video of our buggy ride from our villa to the main lobby. The main lobby was like approaching the castle at Disneyland: