Would be great if people could create an account by just selecting a select box i.e.
Step 1: Returning customer (log in) & New customer
*if clicked on returning customer, auto choose payment + delivery options
* if clicked on new customer, see step 2
Step 2: use same form as 'checkout without account'. At the end ask if person wants account. If (for instance) checkbox selected, create new account with e-mail as username and create random password. Send this info in a separate email.
Step 3 and futher remains the same.