GPS + HRM for the Bikes

I burned my REI Dividend and 20% member coupon on a Garmin Edge 305, which is basically the be-all/end-all of bicycle computers. I got the fully loaded version with the Heart-Rate Monitor (HRM) and the cadence sensor, then went on Amazon and ordered a 2nd cadence unit for the other bike...

I have the unit configured to display seven data points simultaneously: Ride time (stop watch), Current cadence, current speed, ride distance, current time-of-day, current heart rate, and estimated calories burned.

With the GPS and this unit's barometric altimeter that increases the accuracy of elevation data, I can do crazy correlations like notice that as I climbed that easy hill, my speed stayed within a 2mph window, but my heart rate went up 15%. Basically, I'm my own science project now. This week's task: use published mechanisms to establish a good baseline for what my actual max heart rate is. I can download all of the data to my computer and do fun things like analyze my performance over time and even plot course maps using Google maps or Google Earth...