Las Vegas - Shopping or sightseeing?

Meet my shop-a-holic friend, Indy, a UF friend (she now lives in LA) who I’ve been shopping with more than half a lifetime and all over the world. Indy’s idea of bargain hunting is buying her Louis Vuitton suitcase in Hawaii because the sales tax is lower than in LA. But she can spot and grab the best dress on the rack while I’m still fumbling for my glasses!
Here we are in Cabo San Lucas, Mexico. We were supposed to be chaperoning her daughter's spring break trip....a scary thought. If you haven't chaperoned a gaggle of gorgeous college girls on spring break in Mexico, you haven't lived! After a hard day in ‘las tiendas,’ we cured our aching feet with a margarita (or two or three) at Cabo Wabo.
Next weekend, a mutual UF friend’s son is marrying the daughter of a UNLV coach in Las Vegas. We are staying a couple of days after the wedding festivities to explore the sights and hit the stores. I'll be shopping vicariously through Indy, most likely.
I’ve never been to Las Vegas, have you? Anyone have any first hand tips about where to go? Other than the hotel stores? I’ve heard there’s a huge outlet mall, but it’s a long drive and not worth the effort. Suggestions, please.