Which packages need to be installed in order for system mail to be generated from for example a nightly rkhunter scan run by cron?
sudo apt-get install mutt) to read it from the command line on my local machine.
You can also forward the mail onto a "real" email address. I have three servers that all do their system error reporting to the root mailbox. I forward these all to my GMail account by editing
/etc/aliases and adding:
webuser: root root: email@example.com
Obviously you'll have a different setup but if you just want your user's email, stick your username in there with your real email address.
You can create a local email account in Evolution. If the system mails are forwarded to your user you will be also notified about it.