So, indulge me. I've always loved the original by the Waterboys, and Mike Scott didn't pitch this as a Christmas song. However, with the repeating notion of stars above, and the aching desire for relationship, it works as a Christmas song for me. And my (no longer secret) guilty pleasure amongst the rootsy blues and raucous rock songs listed so far is... the absolute beauty Ellie Goulding's cover. From the clipped phrasing to the liquid silky vocals, I'm a sucker for this every time.
"How long will I be with you? As long as the sea is bound to Wash upon the sand.
How long will I want you? As long as you want me to And longer by far.
How long will I hold you? As long as your father told you, As long as you can.
How long will I give to you? As long as I live through you However long you say.
How long will I love you? As long as stars are above you And longer, if I may."