I thought I'd mention a series that I'm slowly working my way through, which people playing merchants might enjoy. It's the House of Niccolo series, by Dorothy Dunnett, which starts with The House of Niccolo (http://www.amazon.com/exec/obidos/tg/detail/-/0375704779/qid=1049942262/armageddonmud). It's set in the 15th century and it's the saga of a merchant house, and does a nice job of conveying some of the flavor of merchant-based intrigue, such as trying to keep a new supply of some rarity under wraps, or various underhanded, money-related deals. I like it a lot so far; I'm about to start the fourth book.
If you liked Robin Hobb's Royal Assassin series, she's started a follow-up trilogy to those, The Tawny Man, which starts with Fool's Errand (http://www.amazon.com/exec/obidos/tg/detail/-/0553582445/qid=1049942596/armageddonmud) - the only volume out in paperback so far. It's the same main character as in the first trilogy, FitzChivalry, and many of the other characters appear, including the Fool and Chade.