Which startup should I go to?

I'm a student at Hyper Island (http://www.hyperisland.com/) in Sweden and I'm going on an internship after the summer holidays. I really want to go to startup in the San Francisco area but I'm a bit unsure which one I want to go to.

I really love what Nest.com, Stripe.com, SquareUp.com and Pinterest.com are doing. They are solving real problems and seem to have a lot of talented people with them.

Where would you go if you where in my situation?

Thanks in advance to all the amazing HN-people.

Holger HolgerE.dk