Apple's claim to the title of "innovator" is a tricky thing. Their most profitable units over the last 3 years have been on devices which have been in the market for a long time. Apple's "innovation" had nothing to do with hardware and everything to do with UI. There is no question that their additions to these markets (digital music, smartphone & perhaps tablet) have been substantial, and the benefits are definitely enjoyed by the consumer.
Apple's dominance in digital music is best described as absolute. That said, as you go through their product line, the more complex the product is, the less dominant their offering is in the market. This is not a coincidence. Apple locks down their systems so tightly that the more you can do on a system the more likely your needs will differ from Apple's offering.
The iPad may very well be a "game changing" device, but my bet is that the way in which the game is changed will more closely resemble what happened in the computer and smart phone markets, than what happened in the digital music market. Which is to say, Apple's offering will enliven the market and increase competition in the space, but ultimately when the dust settles Apple will likely not be the market leader (at least in terms of units sold). I sincerely hope this is the case, because I am a prime example of a consumer who would purchase a tablet machine, but the iPad itself is not likely to ever be an acceptable solution for my needs.
Apple is a great device company, but I think pretty much everyone would agree that Apple's management style is not very pro consumer. Which is to say, both the computer and device markets NEED Apple in them, but as the only, or even the main player.
