Lots of cheaper hotel rooms are available around Xmas. Just about anywhere along the strip is good. Some may be a lot more expensive than others. Shop around, but don't spend too much. Cheaper is better. You will only be sleeping in your room a few hours per 24 hour period. I'm pretty sure you should be able to find something decent for less than 75 per night. I stayed at the Aladin recently, but it's under construction/conversion to Planet Hollywood hotel and casino. MGM is too big, Mandalay Bay and Wynn are too expensive, but places like the Flamingo, Imperial Palace, Luxor, Cesars', Bally's and just about everwhere else is pretty nice. Stay away from Excaliber unless you like kids around.
The days of the super cheap buffets are gone now; most are around 12-15 and up. Lots of really nice restaurants too.
I love Las Vegas, but I find I'm partied out after 3-4 days and I'm ready to go home and relax. I must be getting old...