Its also worth it to decide if you need user email addresses at all, chances are you don't. For most services the only function of having the email address is to spam the user. Yes, there are password resets but you don't have to force it on them, let the user decide if they want to make that fallback available to them.
For better or worse, email has become the primary way of authenticating identity, with Facebook and Google Id in second and third. Password resets are vital if your service is non-trivial, and I consider having some form of it to be absolutely necessary.
