I found a couple pics from a couple years back, they may not be the best examples but this is what I was describing. If I don't cut it and style it the way I do, I have puffy Ben Affleck hair instead. As it is, the hair separates out into sections that hang together instead of being one big puffy mass like when a crappy mall stylist would do it. My hair is still pretty similar to this though I manage the sides a little differently lately. I wish I could find a better style but this is really the only thing that seems to work for my hair.
If my hair weren't so thick the effect would be a little more obvious I think, since there's not much room between the "chunks". This is sort of what I go for:
James Dean on one of his less clean looking days, since that's kind of what I look like through extreme beer goggles.
This is what it would look like with a "too clean" mall cut and I'm trying to avoid:
Here's another example of "chunky" hair (as I'm using it):
Though he verges into dangerous Fauxhican territory in that movie.
I hope this helps since this thread is the #1 google hit for "chunky hair".