Tom Holt - depends which direction you want to go. In the slightly-more-silly direction: Rankin, Asprin, Pratchett; in the slightly-more-sensible direction: Sharpe, Stoppard, Frayn.

Haven't read anything by the other two :-(

Also, in the direction of random recommendations, read _Midnight in the Garden of Good and Evil_ by John Berendt *now*, and then spend several weeks cursing the fact that he hasn't written anything else.