A note on the strapless thing: it really does depend on your college. At many schools a strapless dress would be a big no-no. At mine it would be perfectly okay. The dress code varies so much from school to school -- at a small school with a very laid-back Greek system, you could probably get away with a skirt on Pref night; at other schools it's entirely cocktail dresses (and I think I remember one GC poster talking about prom dresses during Pref night!
). At some schools, rushees dress very trendy whereas at others a more classic look is preferred. Follow what's in your rush booklet, ask your Rho Chi, and if nothing else, go with the option that is the most classic -- for example, you'll probably feel more comfortable in a "strappy" dress if nobody else is wearing strapless, even if it's not a rush faux pas to go strapless at your school.