What're some of the less "preppy" sororities?

I can't speak for most of the sororities you listed. I can only speak on the NPHC sororities or African American sororities (Alpha Kappa Alpha, Delta Sigma Theta, Zeta Phi Beta and Sigma Gamma Rho). Do your research on them before you make a choice. Once you join one of the sororities mentioned above, you are a member for life.