I'm surprised at how many Slashdotters here hate running their own e-mail server. Heck, from reading this thread, you'd think it was impossible.
I have Postfix running with SpamAssassin at home, and it's been stable for years now. Want to solve the problem of outbound mail not being accepted? Just use your ISP's mail server as a smarthost for outbound mail. Worried about security? Honestly, you shouldn't be; just run your distribution's stable build of whatever mail server and you should be fine. Run a quick abuse.net open relay test, and you've taken all the precautions I have. (Well, I've moved my SSH port off the default and installed fail2ban, but that should be automatic for any Linux-based server.)
Running everything on Gmail has its advantages for ease of use, but local mail has its advantages, too. I have a copy of every e-mail I've ever received. That gives me a good feeling. I can browse and search it very fast - sure, the internet is fast these days, too, but there's a small advantage.
And you can set a backup MX record with a lower priority pointing to say, gmail, so if you have problems with your connection at home, the mail will still go somewhere.
Yes, it's not really necessary (gmail is fine) and can be a hassle for some, but is not as difficult as the posts in this thread would have you believe, and it's fun!