CRJ-200 flight crew encountered wake turbulence from the preceding B757 on departure from ATL; resulting in 35 degrees of uncommanded bank.

Narrative

Upon take-off in ATL off of Runway 8R; at approximately 800 FT AGL; received wake turbulence upset from departing B757. Aircraft rolled approximately 35 degrees left while applying approximately 3/4 aileron in opposite direction. Increased climb rate and turn to the right to exit wake turbulence (wind at ATL was reported at 100 degrees at 6 KTS; wind at 800 FT AGL as indicated by flight instruments was 134 degrees at 13 KTS). Exited wake turbulence and informed ATC of our heading deviation and wake turbulence encounter. ATC instructed us to turn immediately to a heading of 70 degrees. Flight rejoined departure SID (SUMMIT4) with no further incident. ATC did say that we should have made our turn to the left to avoid departing traffic off of the south complex; but the winds would have also made the wake turbulence drift to the left; possibly increasing the risk of a further upset/non-recoverable situation. Increasing separation of departing B757 or heavy aircraft from next departure. Using a specific runway only for B757 or heavy aircraft.