I'm not certain if you can get it in the States, but the GHD is hands down the best straightener. It's expensive, but does an amazing job. (GHD stands for 'Good Hair Day' btw.
Chi hair straightener is AMAZING! Before Chi, my hair would frizz the moment I finished straightening it! Yesterday, was at a really hot, crowded party, and my hair was still as straight as ever! I can't say enough about Chi.
I love my Rusk straightener. I hardly straighten my hair now because the style I have requires curls and flips, but man, that thing could straighten anything. I used it on the lowest setting and my hair was straight for days. I did use the straightening products from them too, so that might have helped. No frizzies even in our wet coast weather.
ITA with Zap2it, my HAI convertable was the best "beauty" purchase I've ever made! Although I have used the CHI a few times at a friends house, and that was really nice too!