Use your existing roll of Monster Cable. There's no reason at all not to do so.
This basic question doesn't seem to be getting answered, and at 40 feet you will be perfectly fine and happy with it. I actually love Monster CIPro installation cable due to the high strand count and the excellent flexibility of the jacket in all weather conditions.
If you do run any cable in the wall, make sure it is CL3 rated, like your Monster Cable already is.
I wouldn't buy something new when you have a perfectly good cable to use already that really is a quality cable.