A friend bought me 2-at-a-Time Socks by Melissa Morgan-Oakes, and I love a lot of the patterns in there. I've decided that I have no desire to knit socks two at a time at this point in my life, but I'm happy to knit these one at a time and know that I can branch out in the future if I change my mind.
I like this book so much that I've started another pair of socks from it as well.
It's a gross oversimplification, of course, but I've found that the socks in this book are easier than some of my other books. Cookie A is fantastic, but I have to pay attention when I knit her patterns. I'm finding these patterns to be visually very pretty, but not tricky to knit. It's great for knitting while watching baseball!