http://www.nike.com/ Apparel Vertical Accordion 105 seconds
Nike uses a clean, mostly frictionless accordion-style checkout, with few distractions or unnecessary fields. The navigation is hidden and the gift card/promo code fields are hidden.
On each form, however, there is still room for improvement. The forms can be organized to feel more more intuitive - and thus quicker and lower-effort - by placing short fields (City, State, ZIP) on the same line, or by auto-detecting the credit card type instead of asking the user to select it.
The Nike Desktop Checkout complies with 62% of our recommended best practices.