Examples of Cocoa Technologies for Text Input

Services: am I using a word correctly? I can select it and hit command-=, and OmniDictionary pops up with definitions taken from several dictionary servers. Or I can hit another key combination or select from a menu and a Google search on the selection pops up in Safari. There are many other services that act on text, such as a statistics service that counts words and characters in the selection and a service that converts "humane text" to XHTML.

Spelling: I can get the real, system-wide spelling service.

Cocoa Keybindings: control-e jumps to the end of the line, etc., like emacs (and it's configurable).

TextExtras: an example of an installable Inputmanager, this free package extends the system's text system in very powerful and configurable ways. It adds a word completion service that uses the words in your document as well as a global list (so you never need to type a long word twice), and the ability to populate a menu with your scripts, in any language, that manipulate selected text (much easier than AppleScript), and much more.