When I first became a fan, I always saw the group as being kind of divided. For me, it was Brian and Nick, Kevin and Howie, and AJ was like neutral ground (happy on his own or as part of either of the two other groups). I actually find it a bit strange that everyone seemed to see AJ and Howie as being a strong pair. I never saw that. Weird.
In terms of writing, I love bringing the cliche Frick and Frack pairing into the present day. Since I'm a Brian girl, it's hard for me not to see Brian and Nick as being close. I know that they definitely weren't for a long while, but it seems like they're becoming closer again (or perhaps that's just wishful thinking on my part).
I also love writing Brian and AJ together. Let's face it, the two of them are kind of hilarious when you pair them up.
Even to this day, I will group Kevin and Howie because they are the oldest and come across as being the most calm and level headed. I can actually see them getting along really well in real life.
I don't really see a big connection between AJ and Kevin. Nor do I see one between Brian and Howie. Those are the pairings that I will avoid because I really have no idea what I would write about (other than a fight scene perhaps - LOL)
I said this earlier today in a review, but I will say it again now. I think every single fanfic writer needs to write at least one Nick and Kevin story in their lifetime. Just for me! LOL and they both have to live, they aren't mounting each other and no girl is involved. I'm picky and demanding!
This would be nearly impossible for me! While I love the Nick/Kevin pairing, I don't think that I could write a whole story just about the two of them. Although it may work out if I were to have them "mount" each other ... LOL - KIDDING!