Without a doubt Luigi. I already liked him for the sole reason he was the under used semi-famous guy that was the brother of Mario, but I started to like him even more after playing the Marie & Luigi games.
I can't wait to see someone say ''Birdo''. That will be very funny.
I think that my name says it all. I love Waluigi because his 'stach, his evil look, and his bomb making (evidenced in Mario Kart double dash). Obviously, Waluigi wall the way.