I bought an Aeron chair a few years ago and although it's fantastically comfortable I feel a downside is sometimes I don't move for several hours if I get engrossed in work. Once they are set up right I've not sat in any work chair which comes close.

As I said, I'm not sure that's a good thing because of the length of time I can sit. I do wiggle a bit but often don't even stand up. I was toying with getting a sand timer or something similar to enforce getting up but not sure how those interruptions would affect my workflow.