I couldn't care less about your definition of a monopoly as it's not relevant. Given Microsoft doesn't control 100% of the OS market, it's not a monopoly either. It's completely beside the point. Anti-trust laws do not require a monopoly. They require companies to not actively try to prevent competition. But that's what Apple is best at. The fact Apple has conflicting interests between running a music store, an operating system and selling 100% of the hardware for that operating system means nothing to you and neither does Capitalism and competition. Maybe you would prefer to live in China if you do not like competition. I think you'll like their hypocritical "Buy China" program while our country calls that protectionism. Maybe we are the hypocrites for not standing by our own country and our own products.
I would like to apologize for my previous arrogance. It was uncalled for.
As Aiden Shaw stated before, it's not only a 100% market share that defines a monopoly. It is also how a company uses that market share and whether there are alternatives to the service or product.
In the case of iTunes and Ipod/iPhone it's definitely true that Apple controls 100% of the players for that service and also controls a large portion of the online music market, which flows through iTunes.
However, Apple does not have 100% market share (as you are stating correctly) and there ARE alternatives. For the players you can choose from the Zune, Zune HD, several cellphones, sony players and hundreds of low cost mp3 players. The list goes on and on. The same freedom of choise is present with MP3 download services: amazon.com, legalsounds.com, freerecordshop.nl, emusic.com. Also here the list goes on and on.
The moment a company has a product or service in a monopoly status, is when the customers do not have anywhere else to go for that service. At that point that company can do whatever it wants: deliver an inferior product, stop innovating and raise prices. I do not deny that Apple hasn't done any of these things to some extent (recent price changes in the iTunes store). But you HAVE alternatives if you decide that your iPod isn't fulfilling your needs anymore. I'm sure there are many people that own iPod Touches now that will look at the Zune HD and seriously contemplate switching.
The reason Apple gets away most of the time with less innovation (than we would like) or higher prices is because Apple has a very loyal customer base and we would buy their new gadgets anyway.
Again, sorry for my previous arrogance. I had a bad day.
Edit: I just read your link (dry stuff, will have to look up some pr0n later to compensate..

). The important paragraph in this piece is this:
In focusing on market shares, courts will include not only products that are exactly the same but also those that may be substituted for the company's product based on price, quality, and adaptability for other purposes. For example, an oat-based, round-shaped breakfast cereal may be considered a substitutable product for a rice-based, square-shaped breakfast cereal, or possibly even a granola breakfast bar.
Apples iPod/iPhone and iTunes combination (oat-based, round-shaped breakfast cereal) has numerous substitutable products that can be considered such as the aforementioned MP3 players from Sony, Samsung, Microsoft and all that Hello Kitty chinese and japanese MP3 player cheapo crap (rice-based, square-shaped breakfast cereal).
Edit number two: on the tying paragraph.... I do not know whether they are already under scrutiny for this, but I'm also not sure whether this paragraph completely applies. After all, as an owner of iPod, your are not forced to download music through iTunes. You can download music anywhere and import this into iTunes and transfer those songs to your iPod. I'm assuming that the fact that you have to load your iPod through iTunes (which is free) is no object as it is readily available for Windows and OS X.
The same applies to the restriction of OS X to Apple Hardware. You are free to install whatever OS you would like on a piece of Apple hardware, so that shouldn't be a problem. The other way round is not possible/allowed (installing OS X on other hardware), but there are alternatives (Linux, Unix, Windows). So what is the general problem here? People want to use OS X on hardware that is not supported by Apple. Why doesn't Apple do this?
1. The official reason would be that they cannot provide full support for their OS on other hardware (just look at the problems MS has making windows compatible to every piece of hardware on the planet).
2. The inofficial reason is of course that Apple wants to sell hardware.
I'm sure Apple values both of these reasons probably equally high (one increases efficiency, while the orther increases profitability).
Just to differentiate this a bit consider the following: suppose you like the Zune OS, but hate the Zune as a piece of hardware. Should Microsoft enable the Zune OS also for other hardware such as the iPod? Alternatively: should Garmin navigation software run on TomTom hardware? Should Metroid for Nintendo WII be converted/coded or whatever, to play also on XBOX?