Amady Faye was easily the worst. Absolutely diabolical in all aspects.
Other candidates in my lifetime:
Butt was an absolute liability towards the end as was Geremi but they both had spells of being ok.
Anita offered very little going forwards or defending but at least he was versatile and filled in when needed.
Alan Smith was an abomination all round. Stunk up the squad for way too long.
Stephen Ireland was a fucking joke.
Damien duff was a cunt.