Depends what sort of fight you're looking for...
C. S. Forrester does great, great Age Of Sail naval engagements. I profess a profound dislike for the mundane, but Forrester's Hornblower stories really got me hooked.
David Weber can make vectors and electronics exciting. Again, like Forrester, naval engagements are the order of the day, but this time they're in spaaaace. And are cool.
Akira Toriyama seems to have a pretty good grasp of what you do when you're a walking nuclear arsenal, and puts it to use in DragonBallZ. Say what you will about plot, there's very little that compares to the uncensored combat.
Ancient Viking saga writers (saganeers?) had some nice stuff. Fairly dry, but impressive at times. ("Then Kveldulf put his bearded axe halfway through the helmsman's skull and took his ship." Exaggerated simplicity, the fight was somewhat longer than that. But that's the style of it.)
In a more thread-accurate way, I've heard good things about R. A. Salvatore. I'm not certain whether I'm in agreement, but the guy does write a lot of fighting...