I'll bung this in both threads I've recommended the Kashmir in before, as it might be of use.
What makes the Kashmir really comfortable is that it has a kind of double decker cushion set.
It looks like Costco have a chair in stock now with the same design:
http://www.costco.co.uk/view/product/uk_catalog/cos_2,cos_2.1,cos_2.1.8/155792
It's in their warehouse deals this month at £83.98, so quite a bit cheaper, even when Staples have a sale on. Haven't seen it in the flesh, so I can't tell you for sure it's as comfortable. Two of the pictures on the website make it look nice, but another two make it look really shiny.