The Archbishop of Canterbury is the spiritual leader and chief primate of the Church of England and the entire world-wide Anglican Communion. The incumbent is The Most Rev. Dr. Rowan Williams.
There have been 104 Archbishops starting in 597 AD with Augustine. The current one is Rowan Williams. The link will provide you with a list of all 104 - that's too many to type in.
When 'off duty' Rowan wears normal clothes, just like you and I. When 'on duty' as archbishop, he dresses smartly in a suit, with a reddish purple shirt (as worn by all bishops), a white 'dog collar'...