Your office/work chair

My chair here has had it. About 3 years worth of abuse and its finally given up with one of the arms busting off. So im in the market for a new one and gotta admit the Aeron is taking my fancy, but at £600 there's caution. Also posts like this put me off. So what everyone else planting there ass on for 8 hours(come-on nearly 10/12 hours) a day?