I got married there a few years ago, stayed in the Wynn for a week. We managed the whole week without venturing outside the city or spending any material amount of time gambling, there is so much to do. My wife is addicted to shopping, needless to say the whole strip is one giant mall. A part from being chief bag carrier we did lots of attractions and gun ranges, zoo's/aquariums, 2 shows (Pen & Teller - V. Good, Zumanity - a bit strange), Freemont etc.
We got really lucky, back then the myVegas rewards on Facebook were brilliant and basically got us about $600 of tickets to shows/attractions at the MGM hotels for free, but those days are long gone.
One thing not mentioned here so far is Death Valley, its really accessible from Vegas by car.
I've got 5 nights booked in Vegas this year as a part of our west coast tour, staying in the Encore @ Wynn this time. The difference this time is we will have a car and things on the list this time are Hoover Dam/Grand Canyon, Red Rock Canyon, cant decide on a show yet but want to see something different. I don't think we will have time for anything else.
I'm a bit miffed we will miss Britney by a few days lol!