Personally, I'd love to read most web-pages on an e-ink display, due to the high contrast, minimal power usage, and great readability even in direct light. I don't care hugely about usability for dynamic content, but I'd want fast scrolling with no update artifacts.
Related question: what's the state of color e-ink displays? Seems like it should be possible to produce a bi-stable display with a little bit of color depth, even if just through filters and dithering.