Is the software update normally supposed to take more than a hour for iTunes?

I have a new, just an 1 hour out of the box 27" imac. Set up went fine and I went to log into iTunes. When I clicked on the icon, the system displayed that there was a newer version and did I want to updae te the software. I said yes. An hour later, its still downloading, The screen reads the following:

Installing Software Update...

the install bar is 7/8th of the way completed, and the text below reads:

Less than a minute.

Is this normal? If not, what should I do?

Thanks so much!!!

Carollynn