Windows Vista will be released to the public this Tuesday (Jan. 30th). Early adopters beware, as there are five different versions (well, actually six). The “lesser” versions are purposely crippled to leave out various features. The linked article is a bit long-winded and technical, so I’ll summarize.
Windows Home Basic is for grandma and grandpa. Anyone even close to being a power user will want Windows Home Premium. On the business side, there’s Vista Business and Vista Enterprise. They’re quite similar, with Enterprise having a few more esoteric features. The business versions have more advanced networking support, while home versions are more multimedia-oriented. Finally there’s Windows Ultimate, which has all of the available features.