In terms of licensing and DRM, Windows Vista is in fact restrictive. DRM stands for "Digital Rights Management" - but its name is misleading, and some people suggest that DRM really stands for "Digital Restriction Management" this latter naming is closer to what DRM is!!
DRM is software that uses some kind of encryption such that a downloaded\bought song only plays on one hardware. Similar to activation of windows where the Windows XP (and now Vista) locks itself to one hardware configuration and when moved to a different hardware it stops working. So if you take your hard disk and try to run it on a friend's hardware windows will lock you out!!! You will only be able to unlock it by calling Microsoft's customer support and giving them a proof that you own that windows copy! Same thing happens when you buy a new computer and want to install your windows copy on that computer, you'll have to explain to Microsoft's customer support the situation.
Microsoft allows you to install retail versions of Windows Vista on only ONE computer (unless stated otherwise)... Upgrading the motherboard or CPU will count as using a "new" computer. You are allowed to transfer your copy to a new computer only once (after calling customer support of course). So if you buy a new computer, or upgrade your computer, you would have used your only transfer available. If you upgrade your computer again you will have to BUY a new windows Vista license!! So they even restrict you on how many time you upgrade your computer!!! [On XP all you had to do, is call MS customer support and give them a proof that you own the copy, and they would transfer it as many times as you want!! On Vista, as I explained, you can transfer your copy only once!]
Back to DRM, many music companies provide music that is encrypted that can only be listened to using certain hardware! DRM causes many problems, say you downloaded a song on your computer, you will not be able to run it on your MP3 player for example...
By the way, windows' genuine advantage "calls home" from time to time. Microsoft installed this "feature" on customers' computer without their acknowledgment... This behavior is characteristic of spyware, Microsoft's genuine advantage is spyware, except that for some reason its "good" spyware Microsoft says!!