that field's most important works

Film Roger Ebert hates lists, or more specifically "The 10 Greatest films of All Time" exercises:

"No list of films has the slightest significance, unless it involves box-office receipts. Every film critic I know loathes making lists. Most of us make an annual Year's Best Films List, because that's our equivalent of signing the Hippocratic Oath when you're a doctor. One year I picked the year's 20 best films, and the readers screamed bloody hell. Didn't I know that the rules said I had to choose 10?"

About the only time lists are useful is if they've been prepared by an expert in a field about their field then they can be invaluable for investigating that field's most important works (French New Wave, Philadelphia westerns, dystopian sci-fi).