I'll keep an eye on HR while on the ride but I don't really do much with it after. Avg speed to me isn't that useful unless it's over the same route under similar conditions, or over a longer period of time on multiple rides. That's where I like the reports in Garmin Connect. You can select to show a report by month and compare average speed over time. The idea, for me at least, is that I should see a trend toward faster averages. Cadence is a lot like HR for me, I use it while on the bike but not much after. As for other stuff, I don't really do that much right now except for what Strava offers; comparison of segments. I like to create private segments on typical routes that involve rolling hills to see if I'm keeping my speed up on those. For me anyway that's my weakness. I do fine on flats, I do ok on long climbs once I get into a rhythm, but on rolling hills I have a tendency to want to sit down and spin when I should just get a little more anaerobic and carry my speed over the hill.