1. Labels! As old school as it sounds, in years past, I wish I had printed a few sheets of labels with my contact info, etc. Business cards are great to have too, but labels are handy. When you arrive at ISTE and get your registration bag, you will find that it has lots of stuff to fill out - prize drawings, etc. There's usually an "Exhibit Hall Raffle Coupon Book" with about 100 coupons that require your contact info (if you choose to play). If you are into that kind of thing, save your cards and your time - by affixing labels where contact info is needed.
2. Water bottle. Your ISTE registration bag used to come with a water bottle. It didn't last year, so bring your own just in case. It is helpful to have throughout the day...especially in the southern heat. I always pack snacks too.
3. Backpack. Unless you want to feel lopsided at the end of each day, bring a back pack. I find it much more comfortable than lugging my laptop, iPad and all that fun swag in a shoulder bag.
4. An Empty Suitcase or Duffle Bag. That fits inside your suitcase. This way, if you need to check an additional bag upon return home, you have one. There are MANY times I wished I had a better way to carry all my junk home.
5. Comfortable shoes. Seriously. Your feet will thank you.
Safe Travels! See you in Atlanta.