I am going to toss in my half-cent and say, a clock would be awesome, but I already had a watch to look at on my wrist!
Although I do forget my watch on some occasions...
That's why I have my Zune, I simply think, why have a Zune to have time when I want to kill time by listening to it!
To say simply, I wouldn't have my Zune any other way. :-)