I think INT is the closest to a dump stat. Not CHA, which I like. I think the stereotypical heroic adventurer is more often charming but dopey than clever but abrasive (unless a wizardly-scholar type, which 4e also gets right).Any stat and no stat consistently is a dump stat.
I see Dex dumped most often.
Con is a bit of a god stat in 4e because it gives extra healing surges. Which helps if you are not that smart!
The Backgrounds that affect base hit points I find flavorful actually (the Fated birth ones and couple of others)