I think Apple's current advertising strategy is fine.
Marketing the iPod and iTunes Music Store via commercials, and keeping the focus on the tools and gadgets.
The "operating system" is not a primary focus for most people. It is the "what can I do" mentality that attracts first time buyers to the Mac. The fact that Mac OS X and the PPC architecture are just way too cool, is something only geeks will understand. And I should know... I can talk about Mac OS X to a lot of different people and get absolutely nowhere.
So, I think Apple has the right idea with their current strategy. They're currently wooing the IT industry with their leveraging of UNIX in OS X Server, and I think it is working.
I know some BIG companies have moved their servers to OS X, and more will follow. The transition is transparent to most users, and the bean counters are happy with the lack of licensing fees, etc.
Once you have a server in that sacred, super air conditioned room, you're only one step away from selling those IT guys their very own Macs. And if it is good enough for the IT guys, it is good enough for the rest of the company.
So, advertising Mac OS X is all well and good, but what will it actually get you?
I think maybe saving the 30 second spots for the iPods, and other consumer oriented products is a better way to spend those advertising dollars.