Email Fields in the Form Builder
Following a request we have made a slight modification to the way form builder works. If you include an email field in your form and the form is sent by your store the default way, we populate the reply-to field in the email header with the email field value.
The form will still come from your store email address but if you hit the reply button, your email client should reply to the email address in the form field.
Gmail Issue
For some reason Google will not use the reply-to header in emails if the email comes from the account that you are in. So if you send form emails to the store email address and then deal with your emails in the same account you will find that the reply-to is ignored by Gmail. Why Google does this is unknown.