IPV6-ifying all my boxes -- any gotchas to be aware of?

[Aleksandr Miroslav]

Finally decided to take the IPv6 plunge and turn it on for all my machines
(all VPSs with various providers). I have no particular reason to do this,
but I don't have any particular reason not to either. This is my rough plan:

   - enable IPv6 on each box and reboot it (~10 boxes)
   - ping each box to ensure connectivity (from each box and also from
   looking glass services)
   - restart services to ensure it is listening on both protocols (sshd,
   postfix, apache)
   - publish AAAA records for the boxes and MX records

All my machines are running 10.2, except one which runs 10.1.

I've setup IPv6 on one box and it looks like it is running okay. I've used
HE's looking glass to ping it, and that works fine with no problems.

Apart from some websites and mailing lists, I'm not running anything
mission-critical, but I'd like to avoid snafus if possible. Are there any
gotchas that I should be aware of?

Thank you in advance for any advice.