The MIT Laboratory of Computer Science take the latter approach to an extreme with its Handy 21 project.

CNN: Opinion: The palmtop that ate Manhattan

Since we're hard pressed to think of a scenario where having a calculator and card reader on hand would be essential to your well being -- especially considering that handy "Calculator" app that comes pre-loaded on most every computer these days -- it's difficult to postulate when this awkward combination of gadgets would actually come in handy.

ENGADGET: Uni-Creation's All-in-1 memory card reading calculator