I could've sworn Apple already shut this rumor down last year by stating point-blank that they have multi-year contracts locked in stone with *all* of the labels for no more than $0.99/song?
Granted, "multi-year" could, theoretically, mean "2 years starting from the opening of the iTMS" (which would mean that the contracts are up this April), but that seems unlikely--the *very* strong implication was that the $0.99 price was locked in for at least another 2-3 years.
In any event, there's absolutely nothing wrong with the variable rate concept (charging more for top hits/less for unpopular stuff), HOWEVER, it should be the other way around--$0.99 should be the CEILING for the variable rates, not the floor.
$0.99 for the new hotness.
$0.79/0.69/whatever for the less popular stuff.
Since the cost of distribution is only going to *decrease* as more and more releases switch over to online sales, the pricing should be DROPPING, not increasing.
Of course, this all presupposes that the RIAA aren't a bunch of dicks, which of course they are.