wanting advice on plugin to maintain customer database

I an looking for advice on which plugins to look at for maintaining a database to support customers. The customer should be able to view and edit most of the fields but some should only be visible to the admin.

I would also like to use this to support emails to the user e.g. (support tickets) with a web based form and keep all correspondence in WP and also send replies to them as email.

All assistance gratefully received.
Peter Evans