I actually like Hartsfield, but that may just be a comfort level attained from having spent my entire life flying from it and watching it grow. For the being the world's busiest airport (depending on how you measure), I think Hartsfield does a decent job.
Unless you can get into an airline lounge, however, WiFi isn't free. There is one exception. The E Concourse food court has a free WiFi hot spot. E Concourse is the one farthest from the Terminal, so it probably doesn't make sense to take advantage unless, 1) your flight is leaving from E Concourse anyway, or 2) you find yourself with a long layover. If you do head that way, One Flew South, a restaurant out there is supposed to be very good (I've never tried it).
