January brings the Consumer Electronics Show to Las Vegas. Even for the convention capital of the world this is a huge show, with some 140,000 attendees and 2700 exhibitors. CES is so large that it fills both the Las Vegas Convention Center and most of the Sands Expo Center as well as most of the hotel rooms in Las Vegas, which tend to run at much higher than even weekend rates.
Budget tip for CES? Stay downtown during CES. Many of the hotels there are as nice as the moderate priced strip hotels, and the Deuce bus runs very frequently from Downtown to the Strip 24 hours per day. Rates downtown didn't appear to be any higher during CES this year.
The rooms in Fitzgeralds on Fremont Street were nicely remodelled a few years ago and you'll also find nice rooms at most of the downtown properties. Just be sure to ask for a room change if you aren't happy with the first one they give you.