The best fantasy city I've ever found is Carse, although it's older -- probably about 15 years old by now -- and setting-neutral. (The latter is a plus, as far as I'm concerned.) There's an iso-map of the town, and every single building is described (even if only as "vacant"), complete with NPCs with lots of adventure hooks. The index is first-rate ... if you wanna know where to find a jeweler, you look it up, and all the jewelers in town are listed. And because each neighborhood has its only alpha-prefix, someone familiar with the supplement can immediately tell roughly where each is, even without regard to the map.
Thieves' World -- an old boxed set based on the shared-world anthologies, issued by Chaosium -- was pretty damned good, too, especially for its encounter tables. (I wish I'd kept my copy, just for those.)
Thieves' Quarter: A City Quarters Sourcebook is d20 specific, and the first book and district of a modular fantasy city called "Liberty." Once completed, I imagine it will be the most detailed fantasy city released, at around 600 pages total. (Liberty and Freeport have many things in common, such as a history of piratical rule, but Thieves' Quarter is much more traditional fantasy than Freeport, and much less tongue-in-cheek in some areas.)