The project we are currently running on MOSS2007 is about halfway. Part of the project is to work with MOSS2007 ourselves, the other part is to gather information from site visits in the context of Dutch Higher Education. It's still to early to draw any conclusions, but there is one remarkable issue I'd already like to share with you. This issue comes down to changing one's working process, or one's habits if you like. MOSS2007 provides a lot of functionalitiy and especially advanced users (provided they have the corresponding rights) can make a lot of configuration changes to their environment, without the help of an ICT specialist. Another thing is that using MOSS2007 in the way it's meant to be used (at least I think it is), is that users should get all necessary information from the site, instead of receiving a whole bunch of attachments throught e-mail. If everyone puts down the documents in the Sharepoint site instead of e-mailing it, it would decrease current e-mail traffic a lot. So it's not only getting information from the site, but also putting your own information there. It's a two way interaction. However, in daily practice people have trouble to change their working processes according to the new paradigm. They are very much used to sending e-mails and attaching documents to it. Instead of attaching the files you want to share, you can include a shortcut link if you want to be of help to the receiver of your e-mail. Even better is to let users set an alert on all folders they want to receive notifications in case changes are made. In our experience the alerting function is not 100% reliable, and moreover, you don't know who has set an alert and who has not. So it's not bad to include the link. This way you'll force all group members to go to the Sharepoint site. Some guys have avoidance tactics, by sending you an attachment and ask you to put it on the site for them.
Don't do that! You're not a secretary. If you are sure they have contribution rights on the site, ask them to put it on themselves. If possible you may want to instruct them the first time, but the message is that they do it themselves. This is the only way to change the working processes. During our site visits we have seen that institutes who have more years of experience with working with Sharepoint still have trouble to get users on to the 'new' paradigm.