Sally's always got a special going on. I love to come here if I need serious hair rescue or if I'm looking for nail supplies.
I have found that for nails, there's not a wide variety of colors each time and they do not carry many brands. It's a nice stop to pick up professional-ish tools though.
Meanwhile half the store, if not more, is made up of hair products. Whatever you need, they most likely got you covered. I do wish though that they would carry some brands that are a little more cautious about what chemicals they use in their products. It would be nice to get a healthy / natural alternative.