I've only been to a Luby's once, but at that time, it was a cafeteria, not a buffet.
I hate buffets as a rule, though I did enjoy the small brunch buffet at Beaumont Inn in Harrodsburg, KY. It seems, though, that they are now experimenting with a menu brunch rather than a buffet. http://www.beaumontinn.com/dining.htm
I was in the business class Sky Team lounge at Heathrow over the holidays, and watched a small kid go up to the hot food table, lick her fingers, and use those same fingers to push some hot pasta dish off the serving spoon on to her plate.
As I said, I hate buffets.