I think that good VP should be younger than president. Lieberman was bad choice and Cheney is awful. (I think Cheney can really lessen Bush's possibility. He can maybe please some elder people, but among younger voters he can hurt Bush much. Also Cheney is ultra-conservative who doesn't make easier Bush's plan to pretend moderate conservative)
Unfortunately I will have to disagree there. Cheney was an inspired choice for Bush in 2000, since Cheney's experience immediately cancelled out any perceived inexperience on GWB's behalf. (That said, I
do agree with your description of Cheney as an ultra-conservative.)
Similarly, should Edwards win the nomination he is inevitably going to face charges of inexperience, and would therefore do well to choose someone older. My money's on Graham.