Okay, I have way too many pairings to list that I support. *grins* But the main ones are~:
Russia/America: Like, Cold War sexual tension? Epic. =w= <3
America/Canada: One word: Twincest. 8D
Prussia/Austria: There's just so much history between these two~! <3
HRE/Chibitalia (Germany/Italy): Well, I think these two are one and the same, but still cute no matter which you think off! :'3
and
Fr/UK: Because England is totally in denial about loving himself some France~ |D