I recently was lucky enough to change my old office chair with a Herman Miller Aeron chair. The chair is an exceptional mix of design, ergonomic support and comfort that no other chair (I have tried) even come close to. The Herman Miller Aeron provides the best comfort for long hours at the desk with a natural fit and you should consider buying one if price isn't an issue...

Ergonomic support with PostureFit

One of the most criteria anyone probably has when buying an desk chair is comfort, ergonomic comfort that is. If you are sitting of long hours every day on a not-so-good office chair, you must have already noticed some back problems such as pain in your lower back or worse. The Herman Miller Aeron will take care of you, and I can state it did for me. I have been having lower back issues, problems I never had until I start sitting for hours in front of my computer. The Aeron offers a custom-fitted lower-back support which provides a natural comfortable posture and outstanding lower-back support.

Aeron also means "healthful comfort"

The Herman Miller Aeron has a great suspension, it is smooth to sit down or get up. The seat and the back are made of a strong pellicle suspension system that distributes your weight evenly. Also, this specific material which conforms to each person's shape avoid strong pressure over your body. Also noticeable, the aeration provided by the pellicle, you seat stays cool and comfortable. Something I really like: the soft (and wide!) armrests are adjustable sideways for correct arm support in all positions...for instance if you are typing on your keyboard, you can adjust them to point towards the keyboard to keep your arms aligned naturally with your typing position. If you are using your computer mouse, then you can simply push the armrest towards the outside, once again to leave your arm aligned perfectly with your mouse use.

Aeron also means "adjustable comfort"

This office chair can be adjusted in height, forward and backward tilt (angle, incline, force), armrests height, and you can add some great back support accessories such as the Aeron Lumbar Kit or the Aeron PostureFit Kit to give you even more comfort!

Overall, the chair is just unbelievable. If you can afford a $750 chair (starting price), I can bet you will not be disappointed nor will want to sit on any other chair after you try it out. I have been using mine for almost 2 months now and it has helped me with my lower back issues and comfort for long sitting hours in front of the computer...and all this is priceless to me. I should not forget to mention that Herman Miller offers cheaper office chairs, the Herman Miller Mirra and Herman Miller Celle, these chairs start around $450.