There probably isn't any one best method for every area.
I'm with those who advocate ham radio, but it does have its limitations as mentioned previously. The GRLevel3 Placefile feature is great, since you can simply use your mouse to locate repeaters in a given area. Once you become familiar with areas that you frequent on the plains, you can also program wide area repeater networks into the memory of your radio.
SN and cell reporting to the NWS is great, provided that you actually have service and the systems are not being overloaded.
CB radio is great for aformentioned reasons while traveling to and fro, but I've never heard of an organized CB radio network that, like SKYWARN nets utilizing ham radio, relays reliable reports to the NWS. Distance limitations and general on-air nonsense make CB radio virtually useless in most areas for that purpose.