The firstLineMatch in the Mail bundle is '^From: (?=\w+@[\w-]+\.\w+)', which doesn't match addresses with names. For example, the first line of my emails is 'From: Grant Hollingworth <grant at antiflux.org>'. I changed the match to '^From: .*(?=\w+@[\w-]+\.\w+)' (i.e., check for an email address somewhere on the line).