5) Gareth Bale
Before Gareth Bale became the most expensive player in the world, he was an exciting, free-kick taking full-back trying to make the grade at Southampton, who themselves were at the time struggling to get back to the top flight. His potential was obvious, although very few would have predicted what was to come from him. Had everyone known, it may have been thought that his decision to choose a move to Tottenham over Manchester United was the wrong one (via Daily Mail). Nevertheless, he still rose to the top and United fans were left to wonder what might have been.