I look at everything. And I also look at certain portions of my ride. I try not to over analyze and obsess over every bit of data. I'm mainly just looking for trends over several rides. I don't obsess if one ride didn't provide what I wanted to see. Truth hurts sometimes. <grin>

I use RideWithGPS.com for my data. Like many of the other sites, it lets you look at your data in various ways. I can pick a point on my route and drag out a selection and then just see the stats for the portion selected. I can also create a segment and save it, either private or public, and when I or anyone else with a public ride go over it, I can see what I and them have done on it. Also, whenever someone else has made a segment a made it public, then you'll get to see what you and other did on that too. Try not to use it just to go out and KOM everyone. Use it to base judgments on what you do or don't need to work on. Not everyone that goes over a segments with a public ride were even trying for a best time or even knew they were on a segment.

When new to using GPS's for cycling, I used the free accounts GarminConnect, RideWithGPS, Strava and MapMyRide concurrently for many months. Eventually RWGPS proved to be my most useful for me and I got a premium account.