I travel to Las Vegas for business and pleasure often and have stayed at many hotels on the strip except for the new ones in the City Center.
So I'd probably pick one of those because they are new and clean, lol.
I have stayed in Mandalay Bay, the Hotel at Mandalay Bay, Luxor, MGM, New York New York, Monte Carlo, Paris, Bellagio, Caesars, Mirage, Treasure Island, Palazzo, Venetian, Wynn, Rio.
My favorite is Venetian. The rooms are very large. I prefer the Venezia tower because it's so quiet and I like being able to get to Bouchon very easily for breakfast (the homemade beignets with chocolate sauce and fresh preserves are mandatory when I'm there, lol). I like the dining choices and of course the Canal Shoppes.
My second favorite is probably Caesars Augustus Tower. I like the Caesars resort, I like both the casual and fine dining offered here, I like walking through the Forum. I like the location.
My least favorites are Luxor, Paris, and Mandalay Bay. I love the pool at Mandalay and there are some great restaurants but I didn't like the rooms and I constantly had to wait on elevators--they do not have enough for the number of rooms. I hated everything about Luxor. And Paris had the thinnest walls; I could hear everything the people in the room next to me were saying.
I'm not a gambler so my choices are not based on casinos/gambling.