alancracker - you wanted ideas on who is the greatest Countdowner. This has been discussed in depth on other forums, and any conclusions have been ridiculed by the show's producer. I'm sure we'll be no more successful.
There is some decent data available - not yet going back far enough to include guys like Harvey Freeman, but I think that's being worked on. Since 2000, the three strongest players statistically have been Julian Fell, Craig Beevers and Kirk Bevins. This is based on percentage scored of the maximum available in each round (I'm being kind to the Bevin Boy by conveniently forgetting his initial 2004 appearance, something he'd no doubt be pleased about).
The 9-point bonus for a nine-letter word distorts things quite a bit, since getting an 8 as opposed to a 9 maximum loses 10 points, whereas a 7 against an 8 max loses only 1. One player whose average suffered quite a bit in this way was David O'Donnell, and if the scores are reworked on a 9 for a nine basis, he is only a lttle behind the three mentioned above. Conor Travers is a close fifth, a little way ahead of the last series champion Chris Davies.
Craig Beevers is a tournament Scrabble player, the 2009 UK national champion no less. Countdown was a brief diversion for him, not wanting to confuse himself for too long carrying 2 separate dictionaries in his head, wheras the others are, or were, dedicated Countdowners for a considerable period of time.
One thing to remember is that Countdown is quite a limited game when compared to other intellectual sports like Chess and Scrabble. The guys mentioned above often come pretty close to perfection, so they're not far from having completely mastered the game - something which will never happen in Chess, for example.
By the way, I also like Rachel's dresses, but I don't look at them while I'm playing the game.