MS still has Exchange and Outlook and there's good commercial value left in that until Thunderbird and Lightning smartens up. But Linux is an eye-opener. You can run it with Apache, MySQL, Sendmail, SpamAssassin, Raid, a firewall and a PBX and Webmin on a machine that was relegated to doorstop in the Windows world a decade ago. Truly- dig out a mothballed machine with a slow Celeron and 256mb Ram and it will load a distro like PBX in a Flash, in a flash with MySQL and Apache all set to go- or you can pay $180 for a fanless Atom that only use a few watts 24/7 and runs like a speed demon.
"... They ne'er cared for us
yet: suffer us to famish, and their store-houses
crammed with grain; make edicts for usury, to
support usurers; repeal daily any wholesome act
established against the rich, and provide more
piercing statutes daily, to chain up and restrain
the poor. If the wars eat us not up, they will; and
there's all the love they bear us."
-- Shakespeare: Coriolanus, Act 1, scene 1
