MR Stuff Shareware has thrown their hat into the PIM ring with the release of Tiny PIM 1.3. Tiny PIM allows you to keep track of appointments, contacts, and to-dos, all with a streamlined interface. According to MR Stuff Shareware:
Tiny PIM stores mailing and e-mail addresses, web URLs, multiple phone numbers and significant dates (e.g., birthdays and anniversaries). When you need to find someone, you can search on any combination of fields.
Each address book you create has its own configurable calendar to help you make "to do" lists, schedule appointments and meetings, plan your vacations, etc. There's even a reminder application included which can jog your memory when a special date or scheduled event comes up.
Tiny PIM allows you to import and export address or event data with flexible tab or comma delimited file formats. A sample set of American holidays is included for importing.
Tiny PIM is available for US$10. You can find more information at the MR Stuff Shareware web site.