I may have had mixed feelings about Las Vegas but it was worth spending a couple of days there if only to get to see the Grand Canyon. I booked a helicopter tour from Las Vegas which involved flying over Lake Mead and the Hoover dam, over to the Grand Canyon, a quick pit stop there and then back to Las Vegas and over the Strip. There was a slight mix up (ie I messed up) which meant that we had to make a quick dash for the airport terminal the day before we were expecting and so the whole thing was slightly more stressful than I was expecting. Once we took off though, and all you could see for miles and miles was stunning scenery, all of that was forgotten.
In some ways, I found the dessert even more stunning than the Grand Canyon itself. I love the colours and the way the landscape ebbed and flowed. It was nothing like I was expecting and all the more impressive for that.