You didn't specify your use case, so these are rash generalizations. My opinions, based on decades of film camera (movies) work. Others may disagree.
A ball head is unsuited to following action. A film/video-style fluid head is far better. A good fluid head will cost more than the tripod it sits on.
A monopod is quite useful for short duration video photography of relatively static subject matter, but not as useful for following fast moving action. It can extend your low light still photography performance somewhat.
Carbon fibre tripods are worth the added expense. The heavier the system, the more likely it is to be left in the car.
Lever locking tripod sections are faster and easier to use than rotating collars.
Tripods are essential for motion media production, long exposures or unattended photography (eg time lapse) but otherwise are increasingly unnecessary. IBIS, lens stabilization, high ISO cameras and fast lenses have made this possible.
A friend of mine is an absolute whiz at BIF. He never uses a tripod.