IMHO the best computer games are those which influence the player to continuously re-evaluate the strategic decisions they made in previous turns. The everpresent temptation to tweak (or even reverse) your game plan can put a strain on even the strongest will - and along the way give the player a great gaming experience.
By that criteria I think IT managers for companies that have standardized on Microsoft products must feel like they are in the biggest computer game ever designed now that Microsoft has decided to charge seperately for client access rights to Exchange 2008 and for the right to run Outlook 2007. You can read the gory details here and probably in half a dozen other places, but the short answer is that buying MS Exchange no longer entitles your users to run a "free" copy of Microsoft Outlook unless you are a long term subscriber to Microsoft Software Assurance.
Apart from the fact that Microsoft wants to make more money, there's a strong message here that it's financially worthwhile to be a long term subscriber to Microsoft Software Assurance. This message does need to be reinforced given the lack of tangible financial benefits from that program in recent years.
The other message is that it makes good financial sense to consider alternative mail clients to MS outlook.
... or not upgrade your old copy of Outlook.
... or to consider other email solutions.
Paying the extra money to Microsoft would be my last choice.