Hey, I have a suggestion, if you're fixated on numbers. I subscribe to a service called BIM-Active (you can find out how to download at www.bonesinmotion.com). It uses the GPS capabilities of your cellphone to track speed, distance, elevation, etc of your runs, rides, etc.

I've used it a few times running and the data you get is really cool. Lots of graphs comparing speed changes and elevation changes from mile to mile, also pulls in meteorological info somehow and notes the wind speeds and temps that day. You get a free online blog too.

I would like to start using this more actually, but for some reason, on runs, the stopwatch is still a better motivator for me, so I end up having to use two gadgets, which often still seems like too much hassle... But you might like it as it not only gives your overall average speed, but also gives the average speed of each mile with the elevation change in that mile, so you can really understand where you're slowing down and why. And compare your performance on flats to subsequent flats, and hills to subsequent hills.

Good luck!