I read many BL manga, so I have many favourite couples. But if you ask which is my most favourite one, it will be Asari and Shoui from Ze by SHIMIZU Yuki.
I always like badass uke, very anti girly uke. Asari is a little evil one :"> He is strong, sexy, arrogant, bossy, like to play trick lover. Just look at how he slave Konoe, tease Shoui, make me laugh and happy. He is the QUEEENNN!
And Shoui :3 OMG! I love him! Such an passionate, devoted seme; not to mention very handsome and cool.