An interesting question from Roy Greenslade: Do comment stars make a difference to newspaper sales? (Short answer: Roy thinks they rarely do).
The only example I can think of when I actually bought a paper I wouldn't do normally is - when in Ireland, and in a rural shop that doesn't sell the Irish Times anyway - I've bought the Irish Independent (a title I'd usually avoid) to read Kevin Myers.
He's exasperating, and after reading him for a while, I was a bit shocked to read a piece that had more than a hint of racism. But he's the only writer I can ever remember buying a paper for.