Part of the defining difference maybe how many contexts/locations you do work in or how hard it is to switch a context on the fly. It seems as if the folks who thrive on a short project list and a long S/M list have many clearly different contexts that are physically very separate (long commutes to specific work places, many activities with children that are in different areas, students moving all over a campus etc.) and whose tasks are often driven by bosses but the long project list folks have far fewer contexts and have far more personal control over all tasks. I only really have @computer, @phone, @local town @ larger town and @farm. Every project whether hobby, personal or work is all at the same physical place and it's not like we have hundreds of acres to mange so even though some of my focus areas are by physical location (Red Barn, Hay Barn, West Pasture) it's only because it's easier for me to see them that way. I can walk to any place on the farm in less than 10 minutes. I am self-employed, all my projects are internally generated. Well maybe not all but I can't think of a single one right now that I didn't define and set up.
The only 2 contexts that are really important are the ones in the towns. We have to minimize trips to town due to fuel costs so having all the potential errands, and needs in one place is critical. I combine my Palm Treo tasks by location with a SplashShopper database of items needed by stores so we don't miss anything when we are in any specific store or town.
Hearing other's views and how they do it is always helpful though even if I can't see how to implement them in my own personal system.