The absolute best way to reserve a hotel room in Vegas is to send a cashier's check for $5000 (or other similarly sizable "front money" deposit) in care of the casino cage at whatever hotel you would like to stay at. Then call them 3 days later and ask for a "casino host" and make your reservations through him or her. You will be expected to gamble -- pick a low-percentage game like blackjack or craps and study, really study, how to play before you arrive!

Remember that there are two rates for any given Vegas hotel room, one for Sunday-Thursday night and one for Friday-Saturday (when the entire population of L.A. moves to Vegas for the weekend). So if you are using a service such as priceline.com/biddingfortravel.com, you might well want to bid the weekday and weekend portions separately.