Summer/Garden Phlox (Phlox paniculata) is the big draw in my yard -- even more so than datura. I'll often have several flying around it at the same time. They're using it for the nectar, where as some species use the datura for both nectar and as a host plant. Pentas are also another good nectar plant (and a host for the Tersa sphinx).
Dallas County Lepidopterists' Society
In my yard, it is Four O'clock - especially the lighter colored white and yellow ones. I grow white ones by the front porch for that reason - we can sit out ther in the evening, enjoy the fragrance, and watch the hawk/sphinx moths. I also grow petunias there - and I never get tomato hornworms on the other side of the house!