There is an article in this month's Word magazine about panel show/panel game hosts and which are the best. Here is a list of the ones they mention and their ratings out of 10 (article written by Nige Tassell).
Charlie Brooker from You Have Been Watching - 8
Rob Brydon from Would I Lie To You? - 9
Jimmy Carr from 8 Out of 10 Cats - 7
Victoria Coren from Only Connect - 7
Stephen Fry from QI - 9
Dara O'Briain from Mock the Week - 8
Sue Perkins from The Big Food Fight Quiz - 7
John Sergeant from Argumental - 7
Vic Reeves and Bob Mortimer from Shooting Stars - 8
This list is of course not definitive. After all, there is no mention of hosts of radio panel show hosts like Nicholas Parsons and Sandi Toksvig, or former panel show hosts like Angus Deayton and the late Humphrey Lyttelton.
For me, my favourite panel show hosts are Fry and Humph - probably Humph nudging top. Who is your favourite?