Herman Miller Aluminium Group circa 1993  

Lots of factors in play. Not the least of which are the basic forum rules.
http://www.designaddict.com/node/add/forum
Note item #3.

I am guessing that the most recent, most local, and therefore most pertinent, comparable sale shows a price of $645 Australian dollars.

leif ericson,
Despite Djnorgsy's violation of the forum rules. I find your deductive reasoning in current price valuation amusing. Brilliant reply.

Oh apologies everyone. I guess I should have known that.
My chair arrives in a few days. In the pictures the material looks a little worn or discoloured. When it wears right away, is it common practice to have them reupholstered? Does anyone want to comment on the condition of the chair from the pictures?

Overall condition appears OK to good. Hard to tell without detail pics. Maybe a little faded or grimy in spots. A good upholstery cleaner/stain remover like Folex usually does a pretty good job on these. Just avoid a lot of scrubbing or abrading the weave. Some have even had good luck with liquid dish washing detergent and low-pressure washers. Don't start out too aggressively with cleaning. Reupholstering these is, um, less than a straightforward affair ...to say the least.
The coating on the arms often chips off on Aluminum Group chairs. Some find this objectionable depending on severity. I know that some have removed the coating and polished the aluminum, but I understand that the coating does not come off as easily as might seem.
In all honesty, you have a nice-looking chair headed your way. Great color! You might have paid more than they go for in the US, but to what matter? Enjoy it!

Hi tktoo
Thanks for sharing your knowledge, I really appreciate it. Very excited about my chair arriving!

Dj, browse the archives on this forum to learn more about these chairs than many dealers of vintage examples know. Have fun!
What I'm most curious to know, though, is when you get the chance to spin around in your new chair, will it be clockwise or anti-clockwise?

Haha anti-clockwise of course, that is at least, according to that episode of The Simpsons 🙂

Wow, after having read through a few threads, I'm amazed that you can have the arms re lacquered or stripped and polished. I'm a bit worried that you can't do much about reupholstering though... seems like such a shame. Are there any options, once the material goes?

Probably your best option is not to worry about it. You can wait to decide when the time comes. There's still plenty of life left in that chair.
In the meantime, keep it out of direct sunlight, avoid bashing the front corners of the seat against a desk (that's where they often start to fray), and, maybe, start putting a little away each month into an Eames chair restoration fund for possible future needs, 😉