For note taking I use the open sourced Notational Velocity [1] (actually I use nvAlt [2] which is a fork that has some extra features like Markdown support). My two favorite features are that it can store your notes as plain text files in a folder of your choice, plus there's syncing through Dropbox or Simplenote. Notational Velocity is a Mac app, but with Simplenote you get x-platform support. [1] http://notational.…
Not good for rich text and images and web clippings and such, just great plain text syncing.