A megapixel and a megabyte are approximately the same measure of information. They are both about as big as an image the size of your computer desktop. Most modern cameras have 5 megapixels or so, so the 16MB card or internal memory is just for show. You're expected to shell out more moolah for a decent memory card.

I've got a 1GB in my 8 megapixel camera, and a 500MB in my 5 megapixel camera. The camera before that, I only had 128 MB, but I also bought a portable hard drive/card reader to take on long trips, or to hula festivals and canoe blessings.