For graduate students interested in an academic career, Professor Lennard J. Davis recently offered some excellent advice in the Chronicle of Higher Education. That advice included the following:
I tell my students to plan their dissertation committees with the job search in mind. They should pick professors who not only are skilled in the field of the dissertation, but who also have national and international reputations. Letters from those professors will count a great deal. And as these things go, letters from full professors will count more than letters from associate professors, and so on down the line.
Note the emphasis on reputation and hierarchy. Professor Davis, who teaches at the University of Illinois at Chicago, is refreshingly honest and would make a good adviser for that reason alone. Even better, all of his degrees are from Columbia. Unfortunately, the most understanding professors with the time and willingness to shepherd you through a graduate program are rarely those with the biggest reputations and most fashionable credentials.