A technique I haven't seen anyone post yet is to score the face of the 
bolt with a chisel then use a punch to drive it out counter clockwise.  
This is usually my technique of choice, since I've lost all faith in easy 
outs, except when the bolt is loose enough to turn by hand.  Obviously, 
this only works when the bolt has sheared at the edge of the block and 
not inside of it.

Jack