Buffets, I don't really try to skimp on as far as money...but most of 'em are in the $20-40 range for dinner anyways.
The best buffets in Vegas in (my) order:
Rio Buffet
Bellagio Buffet
Wynn Buffet
Paris breakfast buffet
Mirage Buffet
The Rio is hands down, the King of Vegas Buffets, IMO.
Co-sign Poltergeist on Planet Hollywood, my homegirls stayed there last month and the room was surprisingly pimpish...and only like $139 a night.