Its a tough call, but considering age, all around game, and just making their teams better, I think I'd have to agree with your list:
There's other greats that are in the twilight of their career (or near it) such as Shaq, Nash, and Iverson. The rest of the players listed above are probably the "best of the rest" at this point in their careers, but I'd say these 5 are probably a cut above right now as complete players. Guys like Shawn Marion and Elton Brand are often underappreciated, but some of the more consistent players in the league right now. Maybe not to the level yet of being the "greats" like those above, but very good. Some players like Arenas and McGrady are definite talents, but maybe not enough of "team" guys yet. The same could be said of Kobe I guess, but even though I don't particularly care for him, he is one of the best in the league. Probably the best pure scorer out there right now.