I go to Vegas at least 1-2 times a year, BF's dad lives there. I won't even try to recommend hotels because we've never stayed in one, but I do agree that you'll probably want to stay on or near the Strip. Downtown is usually for people who are more interested in gambling, although if you have a car, I would also pay a visit there to see the Fremont Street Experience. I also have better luck with Gambling there too. If you are going in August or later, a new outlet mall is opening in Downtown too.
As far as things to do, there are MANY, even if you aren't big time gamblers, which BF and I are not. I'll just list them, some may require a car:
* Shows: Mystere, Siegfried & Roy, O, Danny Gans are some of the popular ones and have good reputations
* Outlet Malls: Belz Outlet (near the airport end of the Strip), Primm (an outlet mall on the CA/NV stateline, about a 45 minute drive, sorry, can't remember it's real name!), Las Vegas Premium Outlets (the new one opening in Downtown)
* "Normal" Shopping Malls: Boulevard (my favorite, on Maryland Parkway), Galleria at Sunset (in Henderson, across Sunset Station), Meadows (I think this one was in Northern Las Vegas, have only been there once)
* Malls in Casinos or on the Strip: Fashion Show Mall (on the Strip, just expanded), Forum Shops (Caesar's Palace), Shops at Aladdin (Aladdin Hotel & Casino)
* Mirage: be sure to check out the "volcano show" outside where the volcanoes erupt at night; they also have a "Secret Garden of Siegfried & Roy," I haven't been for several years, but it used to be $10 and the money went to conservation efforts, and you got to see the dolphins that belong to the Mirage and then walk thru a little mini-zoo with S&R's animals (tigers, elephants, etc.).
* Treasure Island: there is/was a pirate show that occured every evening at set intervals...however, I thought I heard somewhere that they were doing away with this, or maybe just changing it?
* Caesar's Palace: there are statues that come to life, and the sky changes from day to night as you walk through. They also have a "Race to Atlantis" ride which I thought was pretty fun.
* Venetian has gondola rides, though I've heard the wait can be pretty lengthy. Still looks like a pretty resort to walk around.
* Paris has an Eiffel Tower and also is very pretty.
* The Stratosphere offers a GREAT view of LV. I've been to the restaurant there several times and really like the food a lot. Pricey by LV standards, but comparable to any good restaurant in other cities. There are also a couple of rides up there. (Unless you're eating in the restaurant, there's a charge to go up there.)
* Bellagio has an amazing water show in the "lake" fronting the hotel. They used to have an art gallery too, but I heard it closed. I've also heard good things about their buffet.
* Red Rock Canyon: I think it's 30-45 minutes away, but if you're looking for something nature-oriented, might want to check it out.
* Mt. Charleston: also about 30-45 minutes away, beautiful just to drive around. They may have a few trails too if you're interested in hiking.
* Hoover Dam: really an awesome sight. You can just stay at the top and walk around, or you can take the tour. Beware if you're claustrophobic though, you have to travel is a small elevator to the bottom, and the ride lasts a while.
* Lake Mead: offers a variety of water craft, boats, jet skis, etc., or you can just go swimming.
Anyway, that's all I can think of at the moment, but I'm sure I'll remember something else as soon as I finalize this post!