Dear Delta Brethren, I've been flying out of ATL for the past few months. This week I was holding short of 26L on the north side of the runway awaiting my turn for takeoff. A DAL 757 opposite me is cleared for takeoff and immediately turns on their taxi light directly in our eyes. It felt like a laser event to us. I flashed my taxi light thinking maybe they didn't see the 767 across the runway but they left the lights on. The next plane to go was another DL 757 and guess what he also blinded us. The sun was not quite up so the lights were pretty intense. Next up an Endeavor RJ, they turned on their runway lights but left off their taxi light. When it was our turn we did not turn on our taxi light directly into the eyes of a MD90 but waited until we were lined up to go. Is it in your ops manual to turn on your taxi light no matter if someone is facing you or not? My F/O begged me to turn on ALL our lights the next time a DL plane lines up across from us. Thank you for your consideration.