1. Francis Jeffers
https://www.youtube.com/watch?v=UOiCkg-SP7I At the age of 20, Jeffers made a move from Everton to Arsenal for an amount which made him one of their most expensive signings at that point - £8 million. Now, at the age of 32 which is considered the prime of a footballers' career, Francis is a fringe player for League 2 strugglers Accrington Stanley (who are they?). If that isn't enough justification for Jeffers being the signing Wenger should regret most, I don't know what is. Though Jeffers has a 100% scoring rate for his country (okay, 1 goal in 1 game), he was unable to live up to his "fox in the box" label when signed by Arsene in 2001. With the likes of Henry, Wiltord and Bergkamp available to lead the line for the Gunners, Jeffers was overlooked throughout his spell at the club and he was also plagued by injuries. This all amounting to a lack of performances and, consequently, a lack of goals during his tenure under Wenger. His first season at the Gunners ended with an FA Cup winners medal for the one-time England international, though he appeared just 6 times in the league and scored on 2 occasions. The following season ended in a Premier League runners-up medal and a further FA Cup win, and Jeffers appeared 10 more times than the preceding season, though scored the same amount of goals. His last apperance was in Arsenal's Community Shields win over Manchester United in 2003 when Francis came off the bench, only to be sent off minutes later. Following this came an unsuccessful loan club back to first club Everton, which amounted to just 2 goals in all competitions and a falling out with boss David Moyes. He was then sold for almost a quarter of his original fee - £2.6 million - to Premier League rivals Charlton. Since leaving Arsenal, Jeffers has been unable to settle down and the veteran has had spells at eleven clubs, with spells in Malta and Australia among them. Now playing in the fourth tier of English football, Jeffers' career has been on a downward curve and ultimately led to him struggling for games at a club that finished 18th last season and almost became non-league. Though injuries played a part, his £8 million tag was premature, especially considering Thierry Henry was signed for just £3 million more in 1999. Juxtaposing what the signings of Henry and Jeffers amounted to shows just how unsuccessful the Englishman was for the Gunners. Transfer fee: £8 million. As this is a subjective matter, there are likely some decisions you disagree with or players that you feel deserve a place in this article. Please share your thoughts below.