The first question is, Which Grand Canyon do you plan to visit?
The four typical portions offer very different experiences:
Most people visit the South Rim -- and all the hotels recommended thusfar are for the South Rim. This is a national park, and it is open year-round. During the summer it is incredibly crowded -- so crowded, in fact, that you're not allowed to drive your private vehicle, but they provide bus transportation. It's, by far, the most commercial of the choices, and you'll find multiple hotels, fast food and chain restaurants, etc. If you want to visit the South Rim (or ride mules), you must make your reservations FAR in advance.
Open only during the summer months, the North Rim is an entirely different experience. It's much more remote, and because its elevation is quite different it's about 10 degree cooler at all times (we stayed there over July 4th, and we never noted the lack of air conditioning). The North Rim is also a national park, and instead of hotels they have small cabins -- they look just like Lincoln Log cabins. This area is much less crowded, but it's also far from civilization -- no chain hotels, no restaurants just outside the park. You shouldn't show up without hotel reservations, but you can expect to get same-day mule rides. They offer an evening program that includes a train ride and a very good dinner. You can expect to see more wildlife at the North Rim.
If you want to actually sleep IN the canyon, you can stay at Phantom Ranch, which is at the bottom of the canyon. If you're in great shape, you can hike in one day and out the next . . . or you can book a mule trip. The hotel at the bottom is owned by the national park system and books a year in advance. Your overnight accomodations include meals.
The last choice is the Western Rim. This is not a national park; rather, it's owned by the Havasupai Indian tribe. You can hike in or (if you have plenty of money) be ferried on a helecoptor. At the bottom you can either camp or stay in their hotel. They have waterfalls and natural swimming pools. This is the least-visited portion of the Grand Canyon, and it takes more planning than the other options.