Shikamaru and Naruto definitely ranks up there for being one of my favorite friendships in this series. There's just something about their dynamic that's about someone who's such a logical thinker that still feels so compelled to be there for a loudmouthed charismatic idiot that does it for me. Not to mention how they both started out as being a couple of complete losers who no one had any expectations for and look at them now.
... Also it's pretty much the closest thing to a 'normal' friendship that Naruto has.