Out of the box Craft doesn't offer a way to moderate new user registration gracefully. Concierge does just that.

When a new user registers on your site, Concierge will:

1. Suspend the new account
2. Send a holding email to the new user
3. Send a notification to a moderator

Once a moderator activates the new user, concierge will send a welcome email notifying the user her account is active. Et voila.

All messages Concierge sends are customisable and can be turned off.

Finally, Concierge can work alongside email validation just fine.

You're welcome :)