The DRM in vista is one of the reasons for not using it.
Long and short of it is that Vista has the most "pervasive and invasive" DRM ever put into an operating system, and it's in all flavors of Vista (not just the "Ultimate" edition, which is essentially the new Media Center edition) because it's buried deep in the Windows kernel. The worst thing to me is the fact that content owners (think MPAA and RIAA) are dictating technology decisions at an amazing level. In some cases the hardware you have today may simply stop being able to play said content in the future because they have built into the OS the ability to revoke hardware drivers at any point in the future, either for technical reasons such as the discovery of "content leakage" or because the hardware company stopped paying their Vista DRM license fees.