I have no problem with Lebron thinking of himself that way. Bird, Jordan, and every other great player probably started thinking that of themselves too soon, even if they never quite acknowledged it publicly.
My problem is when the so called experts follow suit. Somewhere during the mid-nineties sports columnists stopped being the sort of grumpy connoisseurs that needed to be convinced over and over of someone's greatness and started being basically cheerleaders.
Not too long ago, the espn experts were sure that Shaq was the greatest ever. They had even coined the "MDE" acronym. Then it was Kobe, and now its Lebron.
What they don't recognize is that they are comparing a player's peak years to others' entire careers. It is relatively easy to be dominant when you are young and healthy. It is another when you age. The thing that made Bird, Jordan, Russel and others so great was not that they had one amazing season, but that they were better than everyone else even at 34, 35...
Once the physical tools weren't there anymore, Shaq wasn't even the best player in lottery bound teams. Kobe was never able to carry the load alone. As far as Lebron goes, let's see how he is playing after winning a title or two, is over 30, and the physical tools and the incentive aren't there anymore. If he is still dominating when he isn't the most athletic player in the league, and when he has won his championship, then we will talk if he deserves to be discussed on the top 5 ever. Until then, he still has a lot of work to do to be even seriously discussed alongside Pippen, Moses Malone, Barkley and others who were great but are never considered in discussions of who is the best ever.