Avoiding BW storyline spoilers for the most part, but from the little I've heard about N and his storyline, he seems pretty cool and enigmatic.
I just hope he actually gets a longer name, though. (I'm under the assumption that "N" is a codename, and I do not know if his "name" is actually revealed later on in the game, or if N is his name) A single letter as a name is a bit weird, especially for Pokemon characters... The meanings that could be devised are a bit cool, though... For example:
1. "N" in mathematics tends to be symbolic of a variable, and since it can technically be used to represent any number, N could be said to represent the concept of infinity, in a way. This would link him to Kyuremu, who apparently represents the Wuji philosophy. From what I read off Wikipedia:
2. The only other meaning (and this is a loose one) is that in the letter N, it is composed of three lines; two are parallel lines and one is a diagonal. If you cut it down the middle, you sorta get two "V-like" symbols, one facing up and one facing down. The two parallels could represent Reshiram and Zekrom, with the diagonal, Kyuremu, "linking" them together in a sense. Again, this is a bit of a stretch...
I was thinking Nero (the main name I'm considering to use as my player name) could be N's full name; it roughly means skill in Finnish and black in Italian. But due to the connotation with "black"; it's kind of a one-sided name... :\
In any case, the simple letter "N" invites so much mystifying intrigue and is open to various interpretations. :D
Oh, and Touya x Touko FTW! N x Touko just seems...strange. But with how little I know about N, I don't even know if they could match...