Mark Zuckerberg and Priscilla Chan get all the press, but they're hardly Silicon Valley's only pair with ten figures between them. Dropbox's twentysomething CEO Drew Houston just became a billionaire — and we hear he didn't reach that milestone alone.

Houston's file syncing startup is widely reported about to close a funding round that values the company at $4 billion. The deal is said to make Houston, all of 28, a paper billionaire. Along for the ride: Houston's girlfriend CeCe Cheng, a Princeton grad who handles PR for internet dossier startup Qwiki (see photo above). The pressures of startup life notwithstanding — Dropbox has had a particularly bumpy ride — friends say the relationship seems serious.

For advice on how to handle the, uh, challenges that a massive injection of wealth can bring to a relationship, we suggest a double date with any of the other young and ridiculously rich couples in the gallery above. Somewhere expensive. You young pretty things might as well enjoy this bubble money while it lasts.

[Cheng via Cheng/Facebook; Houston via]

CeCe Cheng, left, does PR for Qwiki; reported paper billionaire Drew Houston, right, co-founded Dropbox. [Cheng via Cheng/Twitter, Houston via Gabor Cselle/Flickr]

Cari Tuna was, until April, a reporter for the Wall Street Journal; Moskovitz, 27, co-founded Facebook and is reported to be the world's youngest billionaire. [Tuna via MSNBC; Moskovitz via Getty]

Priscilla Chan met Facebook co-founder Mark Zuckerberg, 27, at college. She's now a medical student who has worked as a Facebook marketer.

Former Facebook president Sean Parker, 32, and actress girlfriend Alexandra Lenas have barely been together a year, but they've already got the media profile of a much older couple.