I’m a huge fan of plain text files, the most portable and universally understood file format there is. They’re easy to search, easy to munge, easy to maintain. New operating system? No problem. I recently had a computer failure, which put my homebrewed backup system to the test, and one part that worked well was my folder of those easily backed up and synchronized text files. I’ve got hundreds (thousands?) of them but they take up next to no room and are easily accessible on any platform including my phone.
I decided though that it would be nice to have them accessible as well via a web interface, and after looking around a bit I decided to try Evernote. Even though it doesn’t have a native Linux client, some of its other features really impressed me, especially the ability to scan handwritten notes, upload them to Evernote, and have them searchable. This also works with cameraphone shots of whiteboards. When you see it in action it feels like magic.