The Waimea Canyon has been compared to the Grand Canyon; it is a canyon, but the experience is so different. The Waimea experience feels more surreal due to the warm breezes coming through the canyon and the incredible greenery. It may sound hokey, but when you're there, it makes "Lost" and "Jurassic Park" come to life! Waimea doesn't feel expansive until you hear then see a helicopter pass through looking like the size of a small bird.
A definite addition to your bucket list!