How do I configure Drupal so that each user who logs is sent to a home page specific to them, or at least specific to a role that he/she belongs to?
I was looking to do the same thing. I need to separate what different users see when they log in. They shouldn't even be aware of other groups and or content that they don't have access to. I haven't tried it yet but here is what I'm going to try. It's maybe not the same thing you are trying to accomplish but might help somehow.
Using themes I will create a separate theme for each group of users and set them as the default theme for the corresponding groups.
In each theme there will be a different set of primary and secondary links but otherwise they will be the same. For example, Group 1's primary links might be "Group 1- project A", "group 1 - project b", etc. and Group 2's primary links would be "group 2- project A" etc.
Set the default front page to something generic like "welcome to ..."
Using the taxonomy_access module and user roles I'll control what content the different roles can view, update, etc.