I don't know if this will address any of Dave's .Mac woes, but Apple is showcasing the next version of the .Mac webmail service. .Mac's webmail has been stuck in 2002 for about 4 years now, so an update will be very nice.
The overall UI has been refined, and it looks like Apple is going for a more 'application' like feel using 'the latest web technology.' Drag and drop, message preview, and keyboard shortcuts will be supported. Apple hasn't said when this will see the light of day but it is 'Coming Soon.'