I have always liked the back end on the series.  The horns on the Furthur are very nice looking.  I would love to one day get a Furthur with a series back end.  I think that the series headstock would better suit it as well.

Do you mean a Point or an Omega? Or like the round back end like the Small Standard? I think a gentle little point would be very sweet looking myself.  
 
The Series and Further share the same Crown headstock shape.

I'm talking about the slope to the back half of the body.