The font is Helvetica Neue Bold, which is also used on the iPhone GUI. Arial is a cheap, imitation variant of Helvetica.
But I think it's a fake, too.
Yup, doesn't change the fact that the title fonts are way smaller than the content fonts... Uhm...
And look at that screwed up antialiasing on the content box in the "Now Playing" movie. Not to mention that the battery life totally changes from menu mode to fullscreen mode.
FAKE!!