Definitely Hulkenberg for me. Alonso’s not going anywhere and won’t respond well to a ‘joint #1′ situation, so guys like Kubica and Webber are out of the picture. Rosberg is quietly de-facto #1 at Mercedes and isn’t going anywhere. Anyone else in the midfield is either too risky/inexperienced at the moment (Kobayashi, Buemi, Perez, Petrov), or too much of a plodder (Sutil, Glock, Kovalainen).
Hulk’s ideal because he’s proved he’s quick all through his career, Ferrari don’t really need sponsorship money from him, but he wouldn’t be too much of a threat for Alonso in the short term. In a couple of years however – as with Massa pre-accident – he’ll blossom.
There’s a caveat to this: Ferrari will have an eye on the road car business’s markets, and they would LOVE to have a driver from Russia, China or India. So if Petrov has a good season… don’t be surprised if he shifts to the dancing donkey at the end of the year.