I may not watch Supernatural anymore but I can tell you right now that the Petrelli brothers from Heroes are more dirty and incestuous than the Winchesters are. I WILL FIGHT ANYONE WHO DISAGREES WITH ME.
It's so obvious that Nathan had his way with Peter a LOT when they were growing up and that Peter loved it like pie. Sam and Dean, on the other hand, love each other like brothers. It is clearly totally platonic.
Also, Nathan likes to KISS Peter and whisper into his ear that he loves him. Whereas Sam and Dean prefer to shake hands heterosexually and play scrabble.
I would do a poll but I don't think we need any more proof than that, do we? No.