I recently finished reading
the Sea Hawk by Rafael Sabatini. I enjoyed it.
The book tells the tale of Sir Oliver Tressilian's betrayal by his brother and the woman he loves, his subsequent enslavement and rise to power, and his quest for revenge against those that wronged him. It includes all of the elements of a swashbuckler, but it doesn't become silly. It's also a relatively quick read once you get used to Sabatini's style, and I found it difficult to put down.
Sabatini was apparently a prolific author, and I'm reading Scaramouche next. I'll let you know what I think!