My "Trends" report in Google Reader:
I "read" everything, meaning I take a 2 second glance and then hit "J" (or next) in my feed items
I "star" something when it is real good, or worth saving for later. I "share" it if it is at least decent. So I think ~2% of what I read is good.
And the stats bear it out, I'm the only person who subscribes to my blog.