[gxti]

I use my own MX rubber-banded together with Postfix, SpamAssassin, and dovecot IMAP. I also have bucket.mydomain pointed to mailinator.com so I can use addresses under that domain as throwaways without the site I'm signing up for knowing about it, although I also use Postfix aliases for long-term throwaways.

My coworker runs his own MX, but bounces all his mail through Google just for the spam filtering.

[bodyfour]

I'm in the same boat as your coworker. I used to run large-scale mail servers for a living, but these days I just can't bear to deal with the spam problem.

I still have hundreds of aliases I've set up when I needed to give my address to some website (more than can be easily/cheaply set up using Google Apps last I checked) so I still run my own postfix server. It does nothing but forward these days.

Thankfully, gmail's spam filters are apparently smart enough to not overly penalize my IP address even though 95% of what it sends them is forwarded spam.