Personally, I think that (in academia) sticking to official e-mail addresses is an atavism.
Currently, one's personal e-mail (say, [email protected]) is better because:
- usually more efficient/stable/etc,
- lasts for longer than 1-4 years.
While name like mad_theoretican_666@... may sound ridiculous for professional communication (but it's rather a matter of taste than anything else), I don't see anything wrong with e-mails like name.surname@ or n.surname@.
However, I heard quite a few times that non-institutional e-mails sounds less serious.
But honestly, if someone builds his/her value depending on how his/her e-mail sounds (and doing it against very practical reasons), it is the thing that is ridiculous.