My favorite pairings? Well, the one in my avatar says it all.
To those who don't know, that's Edward Elric and Winry Rockbell from Fullmetal Alchemist. I also support AlphonsexMei and RoyxRiza, as well as a few shippings like HavocxRiza, AlxWinry, and the ever-famous yaoi pairings RoyxEd and HavocxEd. There's a lot more, but I fear my message might be too long.
As for none-FMA and Twilight pairings... I support KeichixShion (Higurashi), SasukexSakura and NarutoxSasuke (Naruto), AmericaxEngland and ChibitaliaxHoly Roman Empire(Hetalia), and RaitoxL (Death Note).
For book-related pairings... well, I'm a Harry Potter multi-shipper too.
Among my favorite pairings are RonxHermione, DracoxHermione and SiriusxRemus. I also enjoy EragonxArya and MurtaghxEragon (Inheritance Cycle), Mrs. CoulterxAsriel and WillxLyra (His Dark Materials).