So my ~$300 Office Works chair has died after about 5 years. Cushions are flat and it's all rattly and squeaky and so on. And most importantly uncomfortable.
So I'm looking at just going all out and buying a Herman Miller Embody.
www.hermanmiller.com/products/seating/office-chairs/embody-chairs/
...for ~$1800. 
Now, I reckon I will sit 24 hours per week in it, 50 weeks a year, for 15 years. That is, rather coincidentally, 18,000 hours.
= 10c/hour
Before any tax deductions.
Yay? Nay? Why? Why not?
Also: Does anyone own one? How's it? It reviews as awesome (i've been researching about six months).
You get what you pay for.
If not then go ergonomic chairs. What are the asking? Tell him he's dreamin.
If it was me I would buy a cheep $100 chair and then you have an excuse to have a massage every month (with happy ending) $70 = $840. Two years later you are still on the winning side, you can reward yourself with a carton of beer for being so frugal. But hey that me, different strokes for different folks! 
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Go for an economical and economical (also comfortable) chair and get up every 15mins. Your body (and wallet) will thank you in 15yrs.
I can recommend the Varier Whatsit Kneeling Chair - still exy but about $500 less than your Herman Miller. You can mobilise your spine while you sit, so you don't have to get up every 15 minutes.http://www.badbacks.com.au/varier-thatsit-balans-kneeling-chair
Electric adjustable stand-up desk all the way! Got rid of my office chair six months ago and I now stand all day. Love it so much I bought the same for the home office, too.
Only time I sit now is for meetings, lunch and coffees.
ditch the chair..
My boss uses a stand up desk.
My wife uses a fit ball to sit on at her desk.
Both these humans achieve far more than I do in productivity
I ditch the chair on night shifts for... my roll out matress 
I liked the office chair I saw on the tv show the checkout last night I think that it was from fantastic furniture that has a toe or finger severing section on the legs but they will give you a rubber insert to stop this now if you want so its all good .
I'm sitting in my ~$300 officeworks chair that I bought for work, now that I'm not working in an office it's in the home office. Highly justifiable, tax deductable and you're using it 40hrs per week. I will never work in an office again without bringing my own chair.
$1800 is a bit of a stretch if you ask me.
I would go in and spent about 6 hours sitting in one before I laid out that kinda money.
Select to expand quoteevlPanda said..
Now, I reckon I will sit 24 hours per week in it, 50 weeks a year, for 15 years. That is, rather coincidentally, 18,000 hours.
= 10c/hour
Before any tax deductions.
lol.
Sitting for long periods is the new smoking, dude.
Buy a chair that will force you to get up frequently and move your fat arse.
Tax deductions are over-rated.
I was lucky enough to have a ~$2,000 Exec Herman Miller chair at my job before last - don't ask me the model name, but they are excellent. Having said that, as others have said - you should really be getting up often, and my current company is now looking seriously into standing work stations. FWIW My former MD always stood at his desk owing to a bad back and swore by it.
Buy a massage chair for 2 grand and sit in that, everyones a winner. Stand when the back kneading gets too much
I found my back was not liking the time I was sitting at the desk ( I am a builder, and probably spend 1/4 of my work time in the office etc).
I got one of these kneeling chairs a few years back and it has been amazing- never had a back problem since. Before I purchased it I was a bit sceptical, but this chair has been worth every cent at around $450 delivered.http://www.badbacks.com.au/products/products-for-work/office-chairs/kneeling-chairs/qdos-vivid-kneeling-posture-chairs
Clarence
Thanks guys. Some insightful suggestions. I've decided to go with the happy ending.
