spoilers for last season of LOST if you haven't watched it
I quite enjoyed the one that emerged on LOST between Sawyer, Kate, Jack and Juliet. I was never a huge fan of Jack/Kate or Jack/Juliet, but I originally loved Sawyer/Kate and then, to my surprise, was completely thrilled with Sawyer/Juliet and around that time I came to be happy with what they were doing with Jack and Kate, too (and Jack's character as a whole). There were tiny hints of jealousy but nothing really exasperating and they all basically were able to work together (despite Sawyer's rage over Juliet's death).
Another one, probably more fanon than canon, was, of course, Spike/Dru/Darla/Angelus. Or maybe that's just my version...
And totally in my own fanon is the fivesome of Spike/Dru/Willow/Buffy/Angelus in TEAOW&S.
Which I will continue someday when I stop writing big bangs.
Day 24 - A crazy love triangle/quadrilateral that worked out badly?
Day 25 - A pairing that was/would-be adorable, but could never work out?
Day 26 - A pairing that you hated and ended up loving?
Day 27 - A pairing that you loved and ended up hating?
Day 28 - A pairing that you will never understand?
Day 29 - What ship had the best proposal?
Day 30 - Your favorite ship forever and ever and ever!