This is probably my new favorite code snippet for Gravity Forms!
Especially useful if you have several forms with multiple notifications each, this will allow you send to users of the site, rather than specific email addresses. Thus, if a user changes the email address associated with their account, the notification will follow suit. I hope to eventually write a blog post on the details of using it.
If you do put it to use, probably good to note that I may be kind of cheating the input validation for emails, which seems to accept text in the form of merge tags. Not sure if that could ever break saving of your notification in some future release.