What database would you use to store (min) 10 billion objects?

I'm building something that's going to store 2 billion media objects in the short term, with each object having 10+ related objects on top. Think crawler with some interesting extrapolations/filters/etc applied.

Would want to be able to power multiple views on data, mostly in aggregate form.

This is all greenfield: the data exists but i'm starting from scratch to crawl and reformat it. I'm interested to know how you might consider storing the info?

Thanks :)