This is the argument that I keep having with my wife. She wants a iPod mini desperately.. like a sickness but she won't buy one because she heard, via me from macrumors that there would be an update. I keep telling her to just buy it, it will make her happy. Right now she has my old 2G iPod and it depresses her because of its size compared to my newer iPod... so this is totally not a needed purchase, purely about happiness.
My opinion, buy the iPod. The model that is out is fantastic, you will love it.