Sometimes these products get bogged down because of three important problems outside of the control of IT. First off, you need to get in touch with all the upstream vendors to get updates to any sort of custom software that has compatibility problems with newer versions of windows; Vista/7 got a lot more strict about giving admin access, for example, which may cause problems in the updates. Second, you've got to keep in mind the training costs. There are a lot of users who may be brilliant financial minds that can make numbers dance and bow to their whims, but get terribly locked up if an icon changes. Doesn't make them horrible people by any means, but you've got to keep it in consideration when planning a rollout. Finally, you have to keep in mind the petty turf wars. If Joe in Accounting gets the upgrade to 7 before Bob in Legal, Bob in Legal may feel slighted and start raising a holy shitstorm, even if he's scheduled to be upgraded a week later. Upgrades are ugly, no matter when they happen. Sometimes that proactive upgrade project takes many years just because of all the moving parts involved.