I wore red. A lot of people mentioned Ross', Marshall's, and Nordstrom as likely places for red dresses. For any A Phis who are on the 'curvy' side, I bought my dress from
Kiyonna - it was a drape neck sleeveless dress, but there's also a red, long-sleeved wrap dress that's really cute too.
ETA - Congratulations to all the chapters in the PacNW/SW regions who won awards!