I found the article about skill and will very interesting. Students have to have both to be good readers, and its our job as teachers to help develop those things.
After reading the articles and slides on motivation the first thing I thought of at our school is Accelerated Reading. In first grade students are just starting to try out AR. They are not required to take tests or get a certain amount of points. In my class the choice is completely up to them if they want to take AR tests or not, and surprisingly almost every one of my students do take tests and love it! I think passing tests help them feel successful. They are awarded prizes after earning a certain number of points and I think this is a huge motivation for them as well.
I think giving them the choice to do this and not making it a requirement helps make it seem like something fun they are doing as opposed to something they are having to do for a grade. My kids come in every morning asking to take tests and they love checking out books to take home and read with their parents.