If I ever have to make a top 5 all time favourite songs, "Skinny Love" would definitely end up on there. I guess the same would apply for For Emma, Forever Ago if the question is about albums.
While the track is very... sad and melancholic, it's somehow filled with warmth this song is an absolute must in the long winter evenings. The final and very short woo - oh - oh humming is simply the best thing ever.