Which secondary anime couple(or pairing) do you think deserves more love?

[CaptivateMyHeart]

I randomly stumbled across a Shiki/Rima video and I got to thinking. Half the time I think I end up liking a secondary pairing more than the intended couple. I choose Shikamaru & Temari over Sasuke/Sakura/Naruto, Utau & Kukai over Tadase/Amu/Ikuto, BS & Tsubaki and Kidd & Liz both over Soul/Maka(though I love this one too), and various other ones. Whether the anime has romance as a main contributer or not most animes have "pairings".

So what's your favorite secondary pairing?
What one do you think would be good as a primary couple?
And which is the most underrated?