If you have a big budget stay at Cosmopolitan.
If you have a medium budget stay at Mirage.
If you have a lower budget stay at a Go! room at the Flamingo.
If you literally don't care at all what the room looks like because all you will do is sleep there then stay at Imperial Palace.
Check smartervegas.com for deals. It is a reputable site but many people don't know about it.
If you plan to do a lot of pre-trip research then look no further than the Vegas subforum at Tripadvisor.
http://www.tripadvisor.com/ShowForum-g45963-i10-Las_Vegas_Nevada.html
If you are into the 20-something club scene then check out Jackcolton.com.
If you are going during pool weather then check out a beach club or day club. It is essentially like going to a club during the day except there is a pool and everyone is in their bathing suits. My favorite is Marquee, but Encore Beach Club is really popular as well.
Best games to learn before going if you are not a big gambler but want free drinks are video poker and Texas hold 'em. Otherwise, visit the casino gift shops for cheap booze to walk around with. You can ride in a cab and the monorail with alcohol (but not the buses). It's such a novelty and I love it!!