HD-DVD
According to an article on BetaNews you will never ever be able to play HD-DVD or BluRay movies on a Windows Vista 32-bit edition. The reason is simple: in the 32-bit editions of Vista it is possible to install unsigned drivers at the Kernel level and this could allow a smart developer to create a workaround to copy these protected movies. In the 64-bit edition of Vista every driver has to be signed.This is imho a stupid move of Microsoft because I estimate that it will take less than 2 weeks after...