I'd recommend any ceramic flat iron. They're the most expensive, but they're the best!
For curling irons I'd be sure to get one that lets you control the temperature-I had a friend burn off a piece of my hair because the curling iron was too hot!
When I worked at Sally's Beauty Supply we didn't sell any ceramic flat irons, but we sold the heck out of some Gold N Hot curling irons. They came in lots of different varieties & were really popular!