Textarea, You Are A Sunken Nothing
If you're on a mac and use Safari, QuickCursor (http://www.hogbaysoftware.com/products/quickcursor) is a nice free input manager that solves this problem. It lets you use a real text editor (Textmate, BBEdit, Smutron amongst others) in place of a text area. Pressing a hot key opens the text opens the text in your editor, and saving copies it back.Sadly it doesn't yet work in Chrome, but the chrome team is working on it.