I would say that it goes something like this:
1a LeBron
1b Kobe
3 Wade (healthy version)
4 Pierce
5 TMac
6 Melo
To Melo's defense, I think he is the most underappreciated player in the game. I watch him play a lot and he gets hacked a lot and almost never gets called for fouls when a case for going to the line is warranted. LeBron is the one who gets all the star treatment. He can bulldoze his way to the basket and throw up his hands ten straight times and all ten times he gets to the charity stripe.
Wade is another guy who is able to take it to the next level, but he too benefits too much from the men wearing the zebra. In fact, I would contend that Wade, while a terrific penetrator, is a fairly unspectacular jump shooter and all around player, in comparison to guys like Kobe. But that's just my opinion.
Anyway, the topic at hand is where does Pierce rank. We can't underestimate Pierce because this guy is a top 5 most all around, complete player. Very few can say they match or exceed Pierce in that category.
Kobe is definitely better, but Pierce is a better human who is more willing to buy into a team concept.
Same with LeBron, who is selfish to some degree... but he can ball like nobody else can at times. He is just flat out unstoppable. Thankfully for the Celtics whenever he's on, so is Paul. I'd say that based on stats LeBron is the superior to Kobe... as the top 2. After that, it's all conjecture.