Here's one handicapper discussing VP choices:
Top 15 Hillary Running Mates for 2016

My prediction is for an up-and-comer, like Cory Booker, Duval Patrick, or Julian Castro. Indeed, Castro will be a star at the Convention whether or not he is the first Hispanic nominee. With him on the ticket, I see a huge turnout and a Dem blowout. Millenials, Hispanics, and liberals would love that combo, it would castrate (pun intended) Rubio or Bush's infiltration of the Hispanic population, and would install a front-runner for the 2024 race.

Clinton does not show her age as much as the men who are competing against her (and as much as the GOP youngsters hope), and the combination of a younger VP and an experienced Presidential candidate will have some of the same synergy that Obama/Biden had.

A well reasoned argument is like a diamond: impervious to corruption and crystal clear - and infinitely rarer.

Here, as elsewhere, people are outraged at what feels like a rigged game -- an economy that won't respond, a democracy that won't listen, and a financial sector that holds all the cards. - Robert Reich