I was wondering if you guys subscribe to the theory that the ideal heavybag weight for a boxer should be half your bodyweight.

ie: If I weigh 140lbs then my ideal bag weight would be 70lbs,Or perhaps you think the heavier the better..?

I guess most people will probably prefer to use a variety of different size bags to work on different things,However if they could only choose one heavybag what would you recommend..?