I'm a big Cirque du Soleil fan; I've been going to see their shows since 1988 (no, I was not a child at the time: ) and I've seen nearly every show that has traveled to Los Angeles or moved in to Las Vegas.
I just bought tickets for the new Cirque du Soleil show opening in September 2008 called Believe that was created with Criss Angel. This show isn't the usual Cirque acrobatic show, it's a show of illusions, so if you are looking for a show to take your young children, choose another Cirque show like Mystere, Love or O. The show ads warn that this show is "not for the faint of heart".
If you join the Cirque Club you will get advance notice of all new shows as well as discounts on some performances. It's free and they don't spam you with emails. If you just want to go see this show and not join Cirque's Club you can call the Luxor directly and they will sell you the preview show tickets (the performances September 1-10th) at the same 25% discounted price. Preview shows are like dress rehearsals before opening day; I think they are better just because everyone in the show is still excited about opening and the show is as fresh as it will ever be.
I got fifth row center seats for September 10th, so great seats are available as of this post, but they probably will not last. Go have fun!