Okay...With this kind of manga, you KNOW there will be this kind of thread.
Just list out all the couples you like!
1 - Ivan/Yao (Russia/China) All time favorite! I love them together KOLKOLKOL! They're historically true, and China's too cute for his own good aru~.
2 - Arthur/Kiku (England/Japan) Don't know where this one came from...I read a fanfiction on them and was hooked. I've seen loads of MAD's with them, and they look good together.
3 - Francis/Arthur (France/England) Because all that fighting is just pent up sexual frustration. And they go back quite some time, plus they're funny together. And I like to think of them as parents to Alfred and Matthew...lol.
4 - Alfred/Kiku (America/Japan) I really like this one because of their past relationships. And the culture shock would be so funny because Kiku's so reserved and quiet...And Alfred....Well, he's American XD
And it would take of some off that heavy angst.
5 - Ludwig/Feliciano (Germany/Italy, HRE/ChibiItalia) 'I've loved you since the 500's..." End of story. And yes, I do believe that Germany was HRE. And they're practically canon.
No pairing wars!!!! It's fine to like what you like! Hetalia is a win-win kind of series.