No chair for me, although I have a friend who carries one and seems to think it worthwhile. I carry a closed-cell foam sit pad, which I also put under my feet at night. On those occasions when I've used a CCF pad for sleeping, I've found it makes a good chair when combined with a handy rock.

I've been looking at the Nemo switchback CCF pad (for sleeping). It's similar to the z-rest pad, but thicker with about the same bulk when packed. I imagine it would make a good chair, too.