Allyson Felix (Athletics)
The shining star of the US women's track and field team, she is still without an individual gold at an Olympics, having to make do with silver in the 200m at Athens and Beijing.
The wholesome daughter of a Christian minister in southern California, Felix was denied a fourth successive world championship 200 gold in Daegu last year.
Expect to see a lot of her in London if she doubles up in the 400m and competes in both relays.