I get really addicted to games with sort of a collection atmosphere so I had sooo many pins by the end of it (along with almost every item of clothing I could possibly buy). My problem was usually just trying to pick one from all of them. xD;
I love pretty much all the characters. I hated Joshua back when I played it after it came out but now that I've played it again, he's probably in my top 3. But everyone is awesome. (Top marks go to Pi-Face for me, though... as a math major and former art-enthusiast, he really stood out. xD)
Story wraps up... fairly well by the very end. And then you can do some extra completion things to get more notes about the story, if you're so inclined. I like it 'cause it meant the game wasn't really over once I'd finished. (I so didn't want it to be over. xD)