Cotton is always good, easy to sew, and it breathes well, but it gets torn and dirty easily. Personally, for a Kaka hoodie, I would use a goot heavy cotton polymer blend for the main body of it, and then just use a cheap wal-mart fabric for the ears/design/other misc. bits.
EDIT!: best part of using cotton is that you get a free coat out of the deal that you can wear not as a cosplay too. Not the warmest thing, but makes for a good windbreaker.