WiseJoeyD, You can bet on it: HD will be quite demanding on system requirements. For instance mpeg4/Hd.264 (maybe this name is not 100% correct) will require systems as 2 processors Mac G5 or AMD 2 Opteron processors with lots of memory and graphic power. Some people talk about dedicated boards with hardware decoders/enconders. Then you have HDDs (larger capacities and higher speeds). And, 64 bits O/Ss.
DRM is in the cards for new hardware/software (at least with Mac and MS O/S) and the new protections base on discs "finger prints".