Is this a better workflow? 1) user form consist of a) username b) e-mail c) password d) retype password 2) if all of the above is ok, and not already

Is this a better workflow? 1) user form consist of a) username b) e-mail c) password d) retype password 2) if all of the above is ok, and not already in use, allow user access to site 3) if running an e-commerce site, or something that depends massively on their e-mail address actually belonging to the user. a) allow user to see e-mail they specified at login somewhere (my account) b) make user retype e-mail at point of purchase c) make user confirm e-mail before purchase, and change e-mail if no confirmation has been sent (obviously a,b and c are either/or type statements) alternatively, if older users are the problem... first 1/2 of Logans Run anyone?