When writing a swashbuckler, it is important to make sure your hero is using a weapon and a fighting style that suits his character. The time periods that swashbucklers are set in--16, 17 and even 18 hundreds--have a wide variety of weaponry you can choose from whereas in a medieval novel, a sword is pretty much a sword and what weapon people carried was determined by their social ranking. Swashbucklers however, give you a good choice to bristling cutlery, the only thing you must consider is weather your hero is a hack and slash man, or if he's just all dash.
Hack and slash types are those who run full-tilt into things without thought or poetic language. These characters despise the cliché for something more real. If your character is a hardened soldier of many campaigns, with lots of scars to show for it, he's most likely a hack and slash man. His weapon would be something like a saber, a backsword, or one that was sharpened on one side only, making it, generally, a cutting weapon. Or perhaps even a cutlass if your man is a navel hero as a lot of people seem to like to write about. That brings to mind a couple famous names in Jack Aubrey and Horatio Hornblower. Hack and slash could also describe any Scots you might have in this time period. Never ones for dash, they always carried their basket-hilted broadswords which were hack and slash weapons.
Now on to dash. Dash is what you typically expect from a swashbuckler, while hack and slash is more what you would expect from more of an historical novel. My hero, Kilroy Allen from Ballad of the Highwayman has dash. The common weapon of characters with dash is the rapier. Thoughts of Errol Flynn come to mind, I suppose, and you think of the traditional swashbuckler. As this is what is expected of a swashbuckler, you can allow some clichés to come through like heroics, smart insults to the baddie during the final duel and such things as that that we really all love. Now the difference between the rapier and the saber as a weapon (getting technical now) is that while the saber is one sided and used for wide cuts and slashing, the rapier is more of a tightly used, thrusting weapon. Of course you can slash with a rapier just as you can stab with a saber, but the style is different. There is more footwork involved with a rapier, for dancing and fencing go hand in hand, while with a saber, you'll want to plant your feet more and take firmer steps when you do. More like while using a medieval broadsword, but not quite as hacky and slashy. For perfect examples of rapier combat (and rapier wit) go watch The Princess Bride.
Later, I will address this same question for your villains as well. Because there's nothing worse than a lame bad guy. Speaking of which, go take a look at Lynnann Richards' blog and read her article on not axing your villain too soon!