We've released a brand new UCanUse module for DNN 3 and 4 that you may find useful. 

It's called the UCanUse User Redirect module.   You can redirect users based on quite a number of criteria including by security role, multiple security role groupings, by query string, by individual user (yes, user-specific redirects) and much more.  You can also specify a pre-redirect page which you can use for whatever purpose you want (user is redirected to page a before being redirected from there to page b); you can also redirect based on page postback, on receiving an IMC message, or on page load (immediately).  Way too much to explain here; have a look at the user manual by visiting UCanUse.com:  http://www.ucanuse.com/PortalModules/UserRedirectModule/tabid/78/Default.aspx

I invite developers to ask for the code which will populate the triggers table for User Specific redirects; for example if an account is about to expire, you could write a trigger to the table and the next time the user logs in or goes to a specific page they would be redirected to the renewal page, etc.  This opens up new possibilities!