I use the Garmin Forerunner with a $5-10 bike mount (works great) and an optional cadence sensor (40-50). It does everything the Edge does but can also be worn on the wrist.

When mated to good software (I use Sporttracks) its hard to beat.

Forerunner 305 is about 225-230 + 45-60 (bike mount and cadence). I'm not sure how much the Edge is right now - if my memory serves me correctly it was about the same price or a little more expensive with the bike and sensor included.

There is a power plugin for the software that compiles weather data from weather underground and calculates power output. Its probably not very accurate (yet) but its fun to tinker with. Calories are also recalculated in the software (always lower) based upon generally accepted rules of thumb.

-R.