It is only fangirl nature to pair up characters from their favourite anime/manga and put them into romantic relationships and the like.
Lurve. ^_^
Ahem, anyways, I ship (support) the pairing of Pip and Seras, or PxS. It is the only canon pairing, meaning it isn't only hinted at but actually expressed in the manga. There is no better match, even if Seras is undead. O_o There is an excellent explanation to this pairing that can be found here. (WARNING! MANGA SPOILERS!)
