Chairs for good sitting posture

[Valerienne]

I am terrible at keeping a healthy posture while I sit. To be honest, most of the time when I'm using my laptop, I just take it to bed and use it while lying on my side. My main problem is that I simply have no comfortable chair to sit in. I don't know if it's my spine defect, but even the chairs advertized as ergonomic make me slouch.

Can you recommend a good, comfortable desk chair?