I too am surprised that the 3rd generation Nano is faring so poorly. I bought one soon after release and have used it constantly. It plays nicely, the battery still goes forever after three years heavy usage, and it has all the features that most people are ever going to need in an iPod. I know a lot of people didn't care for the squat shape, and the muted colours, but in day to day real life usage I have to say that the shape fits perfectly in the hand or pocket and in my opinion is much more ergonomic than the long skinny shape that followed. My daughter has a 5th generation Nano, and I find it less compact and comfortable to carry around, and the sharp edges on the ends are positively unpleasant when compared to the soft curved edges on my 3g. I do think Apple could have offered more colour choices in the 3rd generation Nano (though I quite like my green one), but that's not the be all and end all of whether something is a good product.
I wonder if the people who voted against the 3G actually owned one, or were just put off by the shape and colours?
In contrast, we were given a 3G shuffle when we bought a computer, and I think it's terrible. Most impractical thing Apple ever produced. Also, my first iPod was a third generation (with the buttons at the top) and while I loved it at the time, and still use it in a sound dock, it had major limitations, not least with the exceedingly poor batteries.