Quick: Who's Billboard's No. 1 Idol of all time? Kelly Clarkson.





With No. 1 out of the way, you can probably guess No. 2: Carrie Underwood. And No. 3 isn't that surprising, either: fourth-place finisher Chris Daughtry.





Then, things get a little tougher. Who's Billboard's No. 8 Idol?





Give up?





Answer: David Archuleta.





The 24-singer list -- based on album sales, track sales and radio plays -- is pretty interesting. If nothing else, it makes for some good trivia for your next party.