I don't think it really makes sense to compare resolution of e-ink to LCD and other back-light screens. Remember those highly magnified comparison photos from few years back (here's a
link on this very site)? You'll notice that is no gap between e-ink capsules but there are between LCD pixels. Even with the high pixel density of today's e-ink screens, they still ultimately have those gaps. E-ink at 165 ppi still mimics paper really well, the letters are just more jagged.
And for that reason I'd rather read text off a Kindle 1 rather than a 300 + ppi LCD screen. And the contrast and clarity of letters is also much better on my PW1 compared to my Kindle 2.