What specific elements should be considered when shopping around for a dive computer?

While each diver has one or two things in particular they want in a dive computer, other elements are wanted and needed by all divers.  For instance, it would be imperative to purchase a dive computer from a well-established manufacturer.  Going cheap on this device could be a matter of life or death so always buy the best.  Therefore, the most important elements include a bright backlight that is easy to read, dive data that can be uploaded to a personal computer for both dive planning and logging, able to handle gas mixes, and intensely tested algorithm specific to calculations for decompression and gas absorption.