I've been to Vegas two weeks ago... I can give you some pointers from a recent perspective.
1-Going to Grand Canyon : it's 5 hours by road, be aware of that. We booked a plane tour which takes 1 hour to get to the Canyon. However the time at the Canyon was quite short, too short since we loved the place.
2-In Grand Canyon you'll need a wide lens, a tele is not really useful.
3-everywhere you go, bring loads of cold water. It,s amazingly dry and hot.
4-In the Canyon, walking around is a must, bring good walking sandals or shoes.
5-Going to the bottom of the Canyon is about 6 hours on foot. Be aware of that if it's in your plans.
6-In Vegas, the Strip is the only place where there are many photo ops. Most of these happen at night. I personally brought a tripod, and that worked well (long exposures mean that people don't actually show on your photos
.
7-Glitter gulch and the Fremont Streetexperiences are ok, no more. I'm not sure I recommend it.
8-Get to the far side of the Bellagio lake from the Paris at dusk and take amazing pictures of the fountains with the Eiffel tower in the background.
9-Be aware that distances are longer than they appear. Much so.
10-The Harra's chain (Paris, Planet Hollywood, Ceasar's, etc) offers the Buffet of Buffet deal : access to all buffets for 24 hours (not "a day") for 40$ if you're a casino club member. That's a great way to eat for a decent price. There are often lines at buffets however.
11-The monorail is not really worth it usually : getting to and from the station means going through the casinos, and that's often longer than walking on the Strip to cover the same distance.
Here's the gallery of my shots (left side menu gives you access to subfolders):
2010-07 Las Vegas pictures by bdery - Photobucket