I shoot the weekly football games for my son's youth football team. I shoot from the sidelines and have pretty good freedom to move up and down the sidelines and behind the endzones throughout the games. One referee even asked me if I'd like to come out on the field behind the offense. Sometimes the camera gets heavy, and I think my focus and IQ would improve, especially in tricky light, with a camera support.
My current rig isn't too big/heavy, but I may get bigger lenses in the next couple years. I also shoot baseball and basketball, and the monopod could be useful in baseball, where there is a lot of standing around between innings and action.
My current system is a D7000 with an AFS70-300 VR. I will probably add an AFS300 f4 for baseball next year, and a 70-200 f2.8VR sometime in the future for shooting under lights. That's as heavy as I'll ever go.
Can you guys recommend a reasonably priced monopod for my use? Also, should I use a separate head? If so, what type, and make? I shoot 95% of my football and baseball action shots in horizontal orientation, and nearly 100% of my basketball shots in vertical orientation). My baseball and basketball shots are pretty much stationary, but I am constantly on the move in football.