Well, I'd NEVER give up being a Delta Gamma; I take a huge amount of pride in my sorority!!
That said, if I had to pick based on other stuff...
ΔΦΕ -- Their philanthropy (anorexia nervosa) is really meaningful to me, having struggled with the disorder myself, and their open motto (Esse Quam Videri; "to be, rather than to seem to be") really intrigues me. I LOVE the unicorn, and their crest is so cool. Also a huge fan of purple and gold. If there had been a ΔΦΕ chapter on my campus, I would have shown a lot of interest.
ΑΕΦ -- I'm Jewish, and that automatically attracted me to ΑΕΦ. I also love the symbolism behind the giraffe (biggest heart, and the head is above all others!). Lilies of the valley are also totally gorgeous... but nothing beats the cream-colored rose!
ΑΔΠ -- They were one of my pref round houses, and I really did love what I saw. Classy ladies, a great philanthropy, beautiful sisterhood. I really loved ΑΔΠ.
ΑΞΔ -- Love the crest, love the colors, love the philanthropy, love the teddy bear mascot. Plus, the DBF is likely going to rush Sig Nu, and ΑΞΔ has ties there.
ΔΔΔ -- I was very impressed with this house during recruitment, but on my campus they tend to be very choosy and usually only take girls with recs. The Tri-Delts I know are very classy and very friendly, and so outgoing and gorgeous inside and out. Such a strong national reputation, too.
ΠΒΦ -- Love the philanthropy, the colors, and the fact that it's got an incredibly strong national reputation. I did *not* like the chapter on my campus.
ΚΑΘ -- The Theta chapter at my college is full of smart, classy, gorgeous ladies who have a huge amount of house pride. I was very sad when I was cut after the second round. Again, super national reputation. Also, I love the black and gold!
ΚΔ -- Finally, ΚΔ. I was a Girl Scout for years and I actively support Dove's Campaign for Real Beauty. Like with Pi Phi, not the best chapter on our campus, but a good national sorority.
There's my incredibly long-winded answer, but still, I'd never give up my bronze, pink, and blue!