dude - here is two cents for you... project vienna is still elusive. Like project "Longhorn", it may also cancelled or the features might changed before the RTM release > it actually become Windows Vista and Windows Server 2008.

One more thing, Microsoft technologies are always similiar in their core. It will never changed. Same windows, same management consoles and same backward-compatible kernels. There is no point waiting coz Microsoft decision will be very predictable. Whatever outcome from project Vienna will be nearly the same as Vista and Server 2008.

Two of the worst factors are the licensing and activation method. They might get worse for users in future release of Windows operating systems. unless you are used to use pirated copies...