Crofty and Ant are my choices every F1 weekend. Red Button FTW. Crofty knows just how to handle situations, and spot strategies, and has a great banter with Ant.
Legard just sounds too posh for F1, and is totally scared of not saying anything for more than 5 seconds.
Ben Edwards is a fantastic BTCC commentator, and I want him staying there.
Top main commentary guys are:
Martin Haven
Ben Edwards
John Hindhaugh
David Addison
Ian Titchmarsh
David Croft
Jamie Whitam
Toby Moody/Julian Ryder
Some sort of Le Mans marathon coverage would be epic with that bunch.