5. Mark Viduka (2000-2004)
With the Hasselbaink transfer fee burning a hole in his pocket, David O'Leary promptly went out and spent £6m of it on Celtic's powerful target man; a purchase that proved to be inspired. Although, given his impressive record of 30 goals in 37 appearances in Glasgow, it's a wonder there wasn't greater competition for his signature. Viduka, like others before him, quickly endeared himself to the Elland Road faithful with a solid 22 goals in his first season, including a sensational four-goal haul in a 4-3 win at home against Liverpool. Although O'Leary imagined he'd form part of a forward three with Kewell and Michael Bridges, serious injuries to them both saw him deployed up front with the young starlet Alan Smith; a partnership that proved lethal during their march to the Champions League semi-final. Like others before him, he was a strong competitor with skill, technique and a knack of scoring great goals. A perfect spearhead for what became O'Leary's babes, who went on to become a major force in the Premier League before the eventual demise in 2004. As a result of the Ridsdale-inspired financial meltdown and subsequent relegation from the Premier League, Viduka ended up joining Middlesborough in the summer of 2004 and like compatriot Kewell, failed to match the success he enjoyed at Leeds afterwards.