1) on Linux and Mac OSX you can use them in terminal, for example:
ctrl+A to go to the beginning of the line (or God, I needed this so much, but was always forgetting to google for it)
ctrl+E to go to the end of the line
ctrl+T to transpose the characters on either side of the cursor
ctrl+D to delete the character to the right of the cursor
ctrl+K to delete the rest of the current line
2) these shortcuts are also supported by Cocoa native text fields. This means, that on Mac OSX you can use them, for example, in your browser’s address bar. Awsome!