The notion that it is somehow wrong that Apple doesn't allow you to install their OS on other hardware is silly, but I think there are plenty of comments already posted that explain that quite well.
What I would address are the comments that indicate you should be able to do whatever you want to with the Mac OS install disc because you paid for it. I would point out that Apple spends large amounts of money on research and development of the OS, and those costs are offset by the profits from the hardware. They develop software to drive hardware sales, not the other way around. If you had to pay a fair retail price (what it cost them to develop the OS divided by the number of copies they sell) for that Mac OS install disc, then it would be a lot more than $129. Basically, Apple sells those discs/software to keep customers happy; they don't have to do it. They could simply say that you must buy a new computer to get 10.5. That's what you have to do with any number of consumer devices. The simple fact that it is using basic computer hardware is irrelevant.
It's really simple. If you don't think Mac OS is worth the cost of buying an Apple computer, look elsewhere. And be careful what you wish for. Should Apple lose, then we are virtually guaranteed that Apple will start charging a lot of money for OS upgrades and we will wind up with a bunch of that registration/license numbers nonsense.
What I would address are the comments that indicate you should be able to do whatever you want to with the Mac OS install disc because you paid for it. I would point out that Apple spends large amounts of money on research and development of the OS, and those costs are offset by the profits from the hardware. They develop software to drive hardware sales, not the other way around. If you had to pay a fair retail price (what it cost them to develop the OS divided by the number of copies they sell) for that Mac OS install disc, then it would be a lot more than $129. Basically, Apple sells those discs/software to keep customers happy; they don't have to do it. They could simply say that you must buy a new computer to get 10.5. That's what you have to do with any number of consumer devices. The simple fact that it is using basic computer hardware is irrelevant.
It's really simple. If you don't think Mac OS is worth the cost of buying an Apple computer, look elsewhere. And be careful what you wish for. Should Apple lose, then we are virtually guaranteed that Apple will start charging a lot of money for OS upgrades and we will wind up with a bunch of that registration/license numbers nonsense.