I was always excited by the e-ink devices. I always wanted one. But they are still too slow to my taste and somewhat bulky to be carried everywhere with me. I like to have an ebook reading device always with me, so iphone/ipod or another universal device of this size is perfect choice for me. This is why I ended up with iPhone.
Before iPhone, I read on all my previous phones (Symbian/Java based). I'm still watching the e-ink developments, but I don't see any chance buying one as long as the page turn is not under half a second or so. I know, I'm weird...