Some good links to click on...

For many of us who are just starting to figure out what we want out of graduate school, what we want to do with our lives, etc... this is a fairly helpful article to get you thinking about the difficult topic.
http://www.gradschools.com/article-detail/what-to-study-96

For those of us who are concerned about what it takes to be a successful PhD student, here are a pair of articles courtesty of Matt Might that I personally love and I think are very illuminating.
PhD in pictures: http://matt.might.net/articles/phd-school-in-pictures/
3 Important Qualities: http://matt.might.net/articles/successful-phd-students/