I use an HM Aeron chair as well. Sitting in it right now, in fact. It's comfortable enough that I don't think about it unless I'm reading a thread about office chairs.
As far as cost goes, some things are worth buying. Akropovic is better than Danmoto. And Madison Seating has the "highly adjustable" version of the Aeron for $525.
Funny thing about working from home. For the first week you can kind of make anything work, but after that you need to recreate all of the stuff you had at the workplace to do your job. Decent chair, place to put your computer, a separate space with a door you can close so the other people in your house can make noise, all of the reference material that sat next to your desk at work...
Basically if you work from home you need a bigger house.
