Android Notedex Notedex uses a cue card metaphor for the interface. You can put text, images, and draw on cards, flip them around and put content on the back. It's fun to play with but needs a facelift.
Android Nimbus Supports Markdown, linking of notes, versioning of notes, great table of contents, lots of online help, inline drawings and images, sharing a public link to a note, notifications, and filtering.
Web Chamu A Web-based note-taking app supporting Markdown, image attachments, easy table creation, and it has an open-source API.