If you need a reminder now and then, and if you want your reminders to appear across all your Macs and (soon) your iOS devices, then give Notificant a try. It's like a digital string around your finger.
Noterize is a sophisticated application for note-taking, annotating PDFs and Powerpoint slides, recording lectures, and sharing. With multiple mark-up options, webpage and websnap insertion, numerous import and export options, and extensive in-app help, Noterize offers users incredible functionality with a beautiful and easy-to-understand interface.
CourseNotes offers students an excellent note-taking platform. Its special features, like premium content, subject lexicons and Facebook sharing, make it stand out from the increasingly crowded field of note-taking applications. Its beautiful user interface (and gorgeous icon) make it a pleasure to use, and when you create note sessions from the main subject screen, the app gets out of the way and lets you focus on typing.