New Barrel?

So I am thinking of getting a new barrel for the Pro Hunter. My only problem is, that I hunt woodchucks and deer. I have a .243 and .30-06 barrel for it already. I was thinking of going into the 45 caliber, like a 45-70 or something. Anyone have a suggestion as what to get? I dont really see a need for another barrel, but once you get one of these Encores, you have to keep buying barrels. It must be an addiction...

What caliber would you buy, and why?
Thanks for the input in advance!
Bob