Cool clothing but also a lightweight jacket. Seriously. This is Texas so anything can happen. Plus interior rooms (especially convention areas) can sometimes be overcooled and get cold. Sunglasses. Toothbrush and toothpaste (you have no idea how often people are asking me for that at work).

Other than that, I'm not very good at telling people what to bring. Since I take my car almost everywhere with me and I've been known to practically live out of my car at times, I always have weird crap with me.