Been to Las Vegas a couple times,
The Cosmopolitan was probably my favorite hotel, its located centrally, the rooms are really nice and they have a lot of really great options for food. (Try Eggslut, great breakfast) It is more on the pricey side, but the other part I loved there was not a huge walk through a casino to get to your room. Every time i stayed I asked for an upgrade and was pleasantly surprised to get a balcony over looking the strip, and if your really lucky you can get a view of the fountains right next door.
The flamingo is another decent spot in the center, its cheaper, and has a nice pool area. It is older but you can book a renovated room and they are fairly priced.
I prefer the pool at the cosmo, and I think they are still running their evening movies at the pool which is always fun.
Stayed at the luxor, but would not suggest it, too far south, and not a great pool.