During the week the prices of hotels are cheap, they shoot up on weekends though as Americans tend to go there for the weekend.
So, Vegas... Amazing.
Hotel wise, Planet Hollywood is good, Cosmo (expensive), Bellagio (good, but expensive), Caesars Palace and maybe Paris are the ones I'd consider. I tend to stay at PH as it's right where you want to be location wise (opposite Bellagio) and the rooms are big, but it's cheap. So this works for me.
When you're over there, the gun shop is great fun, go see a show as they are pretty spectacular. Last show I went to see was Absinthe, you can get VVIP tickets for £70~ each and they're well worth it. Absinthe is amazing, it's basically Cirque meets Rocky Horror show. Stunts are great and the humor is crude - contains very strong language, so if you're offended easily go watch O, if not, you'll enjoy it lots!
Hoover Dam / Canyon is worth a visit, make sure when you visit the canyon you go to the South Rim, the West Rim isn't actually a part of the Grand Canyon and the Native Americans will rip you off - the sky bridge for example is very expensive and they charge you to take pcitures. Make sure you go to the south rim - you can fly there and back within a day with ease. Or take a helicopter down.
Remember, you can drink over there for relatively little expensive. If you're playing a machine a girl will come over and offer you a drink (any drink, champagne, G&T, Lager etc) and will expect a tip, the more you tip them, the more they will come back - but it works out around 1$ a drink minimum, but make sure you're gambling. You can also take your drinks to other Casinos. If you're bored of one, pick your drink up, walk down the street (whilst still drinking) and walk into another Casino - this is fine in Vegas, completely fine.
You could take a trip to old vegas, which is at the bottom of the strip - it's a big trashy, but it's nice to see where Vegas started - I've had discussions with Rotty on this previously, I don't think the gambling is cheaper down there, he does... Go with Rotty, he pretty much lives in Vegas.