Thanks so much for all your great sock yarn recommendations in the comments to my previous post! How did I not know that Cascade had a sock yarn? I'm definitely ordering some of that to play around with along with some of the other yarns recommended. I'll keep you posted.
One of my problems in finding sock yarn is that I get these particular colors in my head and then I can't find that color in sock yarn, like the deep medium pink I want for the piggy toe socks (DrLeonesse mentioned the same problem in the comments) or the rich kelly green I want for the Leaves socks in the Socks, Socks, Socks book.
I did recently purchase some of Elann's Sock it to Me Essentials. Like LaurieM mentioned in the comments, I also thought the colors weren't quite what I saw on the website - they seemed more faded in real life. Still the price is excellent so I guess I'll combine those with some of the other new sock yarns to get enough colors.
HERE is the link to the German sock book I mentioned. Pat told me about it and that there is a possibility of an upcoming translation to English. I used Google Translate and it looks like there are a good amount of colorwork patterns.