I am going out to the Grand Canyon, Antelope Canyon, Monument Valley, and redrock in late May. I currently plan on using my 17-40 but have been reading comments about the image quality at 17mm on a FF camera(will be using either 5DII or III if it is out). I am debating on renting either the 14mm, 24mm, or 16-35mm. What do you guys think? Should I consider a good tele?...
I was up there about 1 year ago with my 7D. I spent more time at Monument Valley than the Grand Canyon. At that time my widest lens was the 15-85. About 90% of my shots were at 15mm (24 for FF) and I didn't really t feel the need to go wider however a few less mm would have been nice. So for FF at MV, 24mm would be fine. I have not been to Antelope Canyon but from what I understand, you will want wide. Based on what you are debating, I'd rent the 16-35 which should be great for all parks. I now have it for my crop and I love it, should be perfect on FF. BTW, I only used my 70-200 a few times, might be more handy for FF shooters.
Time of day is essential for for these canyons. Morning, evening and midday light are like 3 different canyons. My favorite time for lighting at MV is late afternoon since it adds extra warmth and drama to all those red buttes. Lots of hard light and heavy contrast so be prepared. The GC has some many different looks based on time of the day. I prefer sunrise and very early AM. Personally I think MV is far more spectacular than the GC (unless you are going to hike to the bottom or visit the north rim). Speaking of the GC north rim, it is way more impressive (IMO) than the south rim. When at MV, don't just stop at the lookout point at the visitor's center, take the loop road (I think its 11 or 13 miles), you will be glad you did, trust me.
About 100 miles to the SE from MV is Canyon de Chelly (pronounced canyon de shay [long "a" in shay]). If you got the time this canyon will blow you away. If you only do one thing there, drive the south rim out to Spider Rock overlook. Jeep tours in the bottom of the canyon are offered and give you a whole different look.
One final tip, lots of dust, so keep your gear protected. In May it still may be a bit windy, less so in the AM.
Enjoy your trip!