For the southsiders, She's Grill in Peachtree City had some pretty good sushi last time I was home at my parents.

In Atlanta, MF Sushibar, Bluefin are both really good. Personally I'm not a sushi snob so the Rusans sushi buffet from 11-3pm works for me, go there spend $12 or so including tip and eat 20-30 rolls, then go home and not eat until dinner time. Shit got me through college and continues to whenever I'm flat broke.