I used to love buffets in my impoverished university days. Now I only limit myself to the rare Sunday brunch or all you can eat sushi excursion (which brings you the food you tick on a list). And it's more for the variety than value since my appetite has gone way down since becoming a cubicle jockey.

Personally, if someone's holding up the buffet line, I try to go around them and come back to stuff they're monopolizing. I don't think they would/should mind. Obviously this may or may not work depending on a variety of factors.