Neven Subotic, Marco Borriello, Andrea Caracciolo... those are the players with the highest rated heading attribute in 2014 (subotic is a centre back, the other 2 are forwards)
I recommend Christopher Samba though, he has a class heading stat, and his all round strength and defending is amazing
Ryan Shawcross. Tall, good jumping, anticipation, bravery and of course very good heading. I set him to attack the far post on corners (and set the corners to far post as well) and he scores 10 goals per season for me.