A thing that I discovered with SSP Profiles and User properties such as email, seems to Cache at Site Collection

From experience working with accounts in Asia SharePoint is that sometimes an account's email settings can get cached into the SharePoint site collection or SSP's profile.  

For example, you may have a user who you look up and has been double checked by the IDM team to have the correct email address entered into AD and SharePoint people lookup dialog shows it.  However, you find repeatedly you can't pick up their email address in a workflow.

I found that sometimes, you may need to first delete the account from the site collections "All People" view first and then re-insert the user back into all the groups they had belonged to for the changes to get updated.  It can be very time consuming as some users belong to many SharePoint groups  and certainly before you delete the user, you need to make sure at least which important groups they had belonged to as deleting them would shut them out of parts of the system.  If AD groups been used instead then I suppose this problem may be less prevalent but I can't say for sure as in Asia SharePoint, we have had to use SharePoint groups rather than AD groups.

If they have a SSP profile, that profile needs updating and tends to take precedence over their AD settings.  Often the profile import synchronisation service may be turned off to alleviate bandwidth demand, therefore, the profiles may need to be updated manually when required. Once the SSP profile is updated, a background SharePoint job will sync the setting usually on the hour.