Apple, Inc. (NASDAQ: AAPL) gets a ton of press about its ever-popular iPod, but the company makes darn good desktops and notebook PCs too. In fact, the growth of this product segment has been credited in recent years to the 'halo effect' of the iPod: as more consumers buy iPods, they end up buying a Mac as their next computer.

A Bernstein Research analyst notes that Apple's global PC market share has gone up in 10 of the last 11 quarters. In a PC market that continues to find growth as more customers replace older machines and emerging countries buy more new machines, this feat is pretty impressive. Here's the kicker: Apple's U.S. notebook sales have made up about 47% of Apple's Macintosh PC unit growth and 52% of its revenue growth in the company's most recent quarter. Now, which tail is wagging the dog here?

Perhaps it was not Steve Jobs' intention to generate such a spike in Mac sales from such products like the iPhone and the newer iPods, but that may be what is just happening. Apple enjoys a very decent margin on its PC systems, so this is probably a relief to Apple's bean counters.

The problem noted in the report is that Apple's share of the market it likes to play in -- the higher-priced PC market -- is already high, so there is little room for growth there. I doubt Apple would price-commoditize its PCs to the bargain-basement level of Gateway and Acer, so is growth doomed to slow down soon?