I know. The iPhone comes with a decent calculator. However, Calculator+, written by Sarah Ragab, (found in the AppStore) provides a more elegant interface, supports handwriting, and displays both the equation and the result at the same time. It was just upgraded Dec. 21, 2011, and is absolutely free. Stuck on a better option. No problem. Just tell us. Click Comment.
I use HiCalc Free which is better rated, also free and I’ve found to be quite good.
I agree Jeff. HiCalc is better. I’m ditching mine in favor of yours! :-)