Back on my 30th birthday, I bought myself a Herman Miller Aeron chair.
I'd had a few drafting chairs before, including the original one that I bought when I went to the Kubert School. It was one of those tall chairs with a five pointed base with wheels. And, every couple of years, it would break. Maybe I lean too much when I'm drawing, or my floor was slanted or something, but one of those spokes on the bottom would break off. My Dad would weld it back, and it'd be good for a while and break again. I remember more than a few nights lettering Elvira and drawing Raider balancing on the remaining four spokes.
I got sick of it. And, back when I was living at home and had more disposable income, 
Everyone who had one raved about it. So I did some research and then I bought one.
They're expensive, but they're worth it. They come in multiple sizes, to suit their owner. They have seventeen points of articulation, so you can really customize it for your body and posture. They're got a 14 year warranty or so, too. So I knew that if something were to happen, it'd be fixed. I ran the numbers and figured that buying the Aeron would be more cost effective than replacing my current chair every couple of years. So I bought one.
There are purchases you make that cost more than you're comfortable with, and you hope you use it enough to justify it. Then, with the right products, you use them so much you can't imagine how you survived without them. My first Mac was like that, as was my first scanner. Tivo and my iPod are my current examples of things that just work and become part of your life. The Aeron Chair was one of those purchases.
Then, last week, there was a snap. Part of the seat assembly started to pull away from the seat itself. I looked around and checked on the warranty. Still under warranty (and will be for the forseeable future) everything was covered, including shipping, which is a big deal with an item this large. Today, it leaves via FedEx and I'll see it again in a week or so.
I'm writing this at my computer on another chair and it's just not right. Bart Sears, one of my Kubert School instructors, beat into us the idea that when you're at your drafting board all you do is draw. No eating, no reading, just drawing. It helps snap your mind into work mode on those days when you don't want to work.
I've taken that to heart, and notice that I don't draw as well, or at least as comfortably, when I'm not in my studio with my materials at my board. For the next week, it's going to be weird not having the right chair. I think I pushed to get an additional page of LNC done before I had to ship the chair out just in case I get some kind of mental block about not having the right seat.
Okay, I know I've gone on and on about this simple chair, probably more than I should. But it's a great chair, seriously. And you'd be surprised how much your mood and productivity are affected by your comfort and something as small as your chair.