If I might add my two bits' worth ...
Arabians are absolutely wonderful. My riding teacher breeds them, and all her lesson horses are purebred Arabs. Sure, they can be spunky, but I've ridden over a dozen different Arabs, and I've never had a single problem with them being over-energetic.
They have a wonderful work ethic, and plenty of endurance. The Arabs she breeds are amazing all-round horses, and completely beginner safe.
=) They're perfect if you like your horses to have personality. I'm am naturally a shy, nervous rider, but Arabians have done nothing but improve my confidence.