in the 'what to wear' section of our greek tiger, it had two girls wearing strapless dresses for pref night. i previously thought that was a no-no, but if you're going to stick it in the panhellenic's guide for PNMs, then it must be okay - of course, there are always exceptions, you'll want to wear something tasteful and classy, and not too revealing or sexy! (though if you're naturally sexy like me, you might not be able to help it...
joking!)