In the above post I have ommited the ON DUPLICATE KEY part in the first approach (3a).
So the complete 3a answer is:
a) Use the insert query with ON DUPLICATE KEY and a dummy update part - in case that the entry exist the database will not complain nor do anything else - this is the silent approach.
"""INSERT INTO emails (e_to, e_from, e_subject, e_date, e_body) VALUES ('%s', '%s', '%s', '%s', '%s') ON DUPLICATE KEY UPDATE e_date = e_date""" % (e_to, e_from, e_subject, e_date, e_body)
more info for ON DUPLICATE KEY at:
http://dev.mysql.com/doc/refman/5.0/en/insert-on-duplicate.html*Also the table create has different fields from the ones I use later on the examples but this is trivial to change.