Morten Hjerde has taken a long hard look at text input field design.
“Edit-in-place is preferable in most cases. A person can see the context, and the visuals is consistent. Full screen editing is preferable when the user is likely to enter a large amount of text. Predictive text (T9, etc) may only be available in full screen edit.”

Link: The anatomy of a text input field (sender11.typepad.com)
Related:
- Text input methods, again
- Predictive text input for PCs
- Survey of mobile text input design
- Text input, upside down
- Designing 2D scrolling spaces
Tags: data, input, interactiondesign, ixd, text, textinput, typing, visualdesign