Well, after some hesitation I decided to post my chart. Its for my 9mi commute, directions not separated as its essentially flat with about a dozen intersections with lights.

The blue boxes are where I changed my bike set up. 'MTB' is my 35lb Diamondback with center tread slick. 'Clipless' is when I changed from loose clips/straps. 'Poprad' is when I started using a Lemond Poprad cyclocross bike set up for road with slicks. 'Fixed' is when I started using a 48x17 fixed gear bike.

A few observations:
-Max, Av, Elapsed Av follow each other. Max speed is not a significant burst, but 1mph less of max is typcial of what I get up to between stops. Big peaks/dips are results of significant tailwind/headwind primarily.
-Fixed gear bike slowed me down, but only after riding it a bit. This one I am curious about as the change was not immediate. I also toward end of summer got tired of pushing myself in 110-115 F heat and since its cooled still enjoy the slower pace. Not sure what all the factors are for my peaking then decline, leveling off.
-I hope this explains what I meant above about average trends, even though there are day to day fluctuations due to traffic, wind, etc.

Al