The good folks at the Miami-Dade Public Library System not only have a great online web-based catalog, but they are participants in the Wowbrary project to provide RSS feeds of new acquisitions by topic.
Check out the RSS Feeds for the Miami-Dade Public Library. They also have similar feeds for many other libraries around the US.
Miami is indeed erratic about providing quality public services — but the public library system is one of our hidden treasures.
The library system here has been my favorite discovery since graduating law school. And since I read around ten to twelve books a month, it has saved me from being poor. And having to use books as furniture.