Many moons ago, Rincewind was my favourite. Just for the line, "I don't mind falling, it's hitting the ground I don't like". These days it's impossible to pick one. Whenever I try, I get a mental picture of all the rest looking sad, hurt, and betrayed while mentally hearing mutters of," We made you laugh", or "You liked it when I did that", and worst of all the mental image of Granny Weatherwax squinting her eyes at me, and nodding once before walking off smiling. *shudder*
All I can say then, they're all brilliant. Even Mr Clete.