Black. Readability should trump aesthetics (especially on search results). Maximum contrast, plz.

It was my understanding that dark grey was actually better than black for readability? Granted, much darker than Duck Duck Go is currently using.

Also on readability: I find the search result synopsis far too wide for easy reading.

I've noticed that the increased width can make it a little awkward to read, too

I really like #333 myself. Nice and dark, still a bit softer than black.

Or maybe add an option to your settings to allow users to pick their own.

This would satisfy everyone from the people that like your grey to the black and the #333 guy.

90% of your users probably won't touch it, but the ones who would may appreciate it.