I've found it incredibly useful to be able to just start typing in an input box, and have a long table get pared down to only what I'm looking for. See Drupal's Module Filter for an example. Since I have an app I'm working on that will eventually need similar functionality, I wrote a quick proof of concept. It's rough, and I have no idea how well it will perform on large tables. But it might come in handy. Visit it on GitHub: https://gist.github.com/4028731