I've been using Beeline Reader which is basically like a Readability bookmarklet that also colors alternating lines of text subtly to make it easier to read things quickly. There's a sort of silly test on their site which showed that I read 26% faster with the Beelined text, and they claim to have performed a study that showed a 10% improvement in reading speed. I'm still skeptical, but I find it more enjoyable to read using it. Maybe I just like stuff that has "Bee" in the name, though.
Some discussion at Hacker News here.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.