The Epsilon Gamma chapter of Sigma Alpha Iota:
They seemed like really fun, laid back girls, and a group with a focus on music really intrigued me. And, as a scared freshman wanting to be Greek, a group of 10 women I already knew (most of them anyways) seemed a lot less scary to me then one of the social sororities with 70+ sisters.
Also, one of the reasons I chose not to pledge an NPC sorority was that I felt, as a music major, I would not have time to devote to a sorority and still grow as a musician. SAI was just perfect because they automatically schedule around all the fine arts dept. happenings and so it worked out wonderfully in my schedule!