I don't see why the poll is being limited to eink. I read entirely on a Nexus 7 tablet these days, but regardless of eink/tablet, I always used a cover. Solely because reading one-handed in bed (or just about anywhere, really) without one is impossible for me. I'd never buy another cover if I didn't need one just to hold the device comfortably.
(don't worry, I didn't actually vote in your eink-only poll
)