Clicks on Sign Up - goes directly to create account page. After creating account takes to my account page (signed in version).
Clicks on my account - goes directly to My account page (which says 'Your account - dont have an account yet - create one now')
Existing customer clicks on my account OR sign in takes him to my account.
If he clicks on anything, eg. view order system it takes him to Login page, then to relevant page (in this case order history page).