I have two chairs that I alternate. One is the standard Office Depot Cheapo chair, maybe $120 or so. Pic is something like it. I'm not crazy about it, but it gets the job done. I keep it in the playroom so I can post on getbig, surf politics, watch ABC videos, etc while doing the dad thing all day.
At night, I sit in my recliner in the office. It is way more comfortable and allows me to put my feet up and work hours into the night (it's 3:25 AM EST as I type this). I do fall asleep in this chair every now and then. I have a keyboard in my lap, and a TV mounted just to the right of my computer, so I can watch TV and work on PC nonstop. It's not a perfect system, but since my work day is split up into 5 or 8 mini-work shifts, its a workable split.