All 3 are special and in the same league. IMO James is a Champion at 160,168,190,HW. The total package of what James has done at HW makes him simply amazing. We are not talking about jumping up for 1 hand picked fight with James. We are talking about facing a long string of HW's and not 1 of them to this point being able to stop him. He had some rough luck with results on Ruiz, Rahman and Peter but that does not take away from him being a MW legend at HW. Top Notch Campaign really and IMO the most impressive thing any of the 3 has done.
Jones' resume was more diversified because he became champion in 4 different divisions. He beat Hopkins, who later became a unified and undisputed champ in that very same division. He also became the unified champ himself at Light Heavyweight. Hopkin's biggest wins were all against guys who were moving up in weight, which meant he always had the upper hand, with the exception of Tarver.
You can't blame Jones for not defeating a unified, or linear, undisputed champion when he himself unified the light heavyweight division. He also beat "the man" at 168, in Toney.
Yeah, it's really hard to pick. Toney has the success at higher weights, Jones has the most dominance in his prime, and Hopkins has the longevity.