Filemaker Pro is a tool for creating custom databases which are easy to use and easy to modify. It works everywhere: on a Mac, on Windows, and even with just a web browser. Every business needs a custom database, and Filemaker is far superior to Microsoft Access or SQL Server.
I love it.
These screenshots are derived from a project I did for Grace Chicago Presbyterian Church, which needed a membership database, and a system for managing the people who wanted to volunteer. After it was completed, I realized I could rip out everything that was specific to running a church, and reuse most of my work for a project in a medical office. And since most database projects start with a need to keep track of people, this will be a useful generic starting point for many other projects.
My generic "People" database can be downloaded from here.
It is free software; you may use it, modify it, and redistribute it.
(Or you can hire me to make it work for you.)