We don't need six versions of the same OS. At best, we need two just like XP:
Windows Home (parental controls, DVDs, etc.)
Windows Professional (everything)
If MS *has* to have activation, then three editions:
Home and Pro with standard activation. Then, Pro VLK with -zero- activation. No KMS servers, just zero activation code like XP. Microsoft can yank compromised volume keys in seconds with WGA, so having a dedicated enterprise edition for SA customers is pointless. Pirates will have it cracked in seconds so activation doesn't affect them. For companies, the sledgehammer of the BSA/SIAA will ensure they have their licenses in order, so activation isn't needed in the business/enterprise world.
MS needs to take a look at other OS makers At most they have two production editions. Six editions for the client OS (and likely 3-4 for the server) is annoying:
Apple: OS X, OS X Server
Solaris: OpenSolaris, Solaris, Trusted Solaris
RedHat: RHEL Desktop, RHEL Server
AIX: Used to be AIX for Servers, and AIX for Workstations, only difference was amount of users allowed on at a time. These days, these two editions are merged.
HP-UX: HP-UX, one edition.