Believe it or not. I sit in here more than 8 hours a day: http://www.ikea.com/es/es/catalog/products/10255307/
It happen me to move on a new apt. my old office chair was a bit old, and it was terrible weighty and big to transport to this new place. I had to save up space on the van so this Ikea chair, yes, a 9 euros chair became my daily chair. The first weeks it was painful, but I had to waste the money on other important things. Now that the cash is flowing I'm thinking in buying one. I guess it will be the Aeron, once of all, the chair I always wanted.
Please share your's, it doesn't matter the model, the price.
PD: at work i use a normal office chair.