Vegas is a definite must-see! I've been there twice. Just go out and take in the sights. Walk up and down the strip and take a bunch of pictures. Then do a little gambling (even if that's not your thing). Take in a show or something.

It's definitely a cool place to visit for a few days.

Oh, and if you want to, go see either the Grand Canyon (about 4 hours away) or the Hoover Dam (an hour or so?). I saw the dam and it's a nice side trip.