Mmmh, good question...
With males, I have to choose Kyon from Haruhi Suzumiya, that guy is just an average joe, minding his ow bussines but he got involved with the weirdest things and, even then, he doesn't lose his sarcasm actitude.
And with females... dunno, Kagami Hiiragi from Lucky star. Because, well, I really like tsunderes and laughing, and with Kagam I got both