“Mountain View,” Paul Graham intoned, “is sort of the center of Silicon Valley.”

The co-founder of Y Combinator was speaking of the city’s place on the map while showing a recent visitor around his startup hothouse. But there’s a strong argument that the title applies in another important way.

San Francisco may get the sizzle, and prices for Palo Alto office space may be soaring, but quiet little Mountain View could be the heart of the valley’s startup landscape.

Consider the big-kahuna investors who gathered at Y Combinator’s semiannual Demo Day last week. As a gaggle of geeks pitched their fledgling companies, Netscape co-founder turned venture capitalist Marc Andreessen sat next to Michael Ovitz, the former Disney president and longtime Hollywood power broker. Ron Conway, tech’s most high-profile angel investor, held court not far from actor/heartthrob/Web 2.0 impresario Ashton Kutcher.

Thanks in part to the city’s biggest corporate tenant — that would be Google (GOOG) — startups are flocking to the scene. They range from classic, two-guys-and-a-surfboard garages to the more buttoned-down offices of online-video provider Ooyala, which has landed $44 million in venture backing and counts ESPN and Dell among its customers.

“Shortly after we moved to downtown Mountain View, it became like a Google refugee camp,” said Ooyala co-founder Bismarck Lepe, who left the search giant in 2007 to hang out his own shingle.

Google owns or leases more than 4 million square feet of office space in town and is making plans to boost that by at least one-quarter. Ex-Googlers have spun off a host of startups nearby, and the company’s venture capital arm incubates a handful of its own.

Microsoft, meanwhile, boasts a 32-acre campus in town that’s the hub of the software titan’s BizSpark outreach program to startups. Then there’s 500 Startups, the incubator launched by early PayPal employee Dave McClure that opened shop earlier this year atop the city’s tallest downtown high-rise.

As for Y Combinator, it ended up in Mountain View through serendipity: Co-founder Trevor Blackwell had extra space in the headquarters of his robotics startup, Anybots.

“People want to be in Palo Alto, but they can’t afford it,” Graham said. “Mountain View’s livable, has good weather and is near San Francisco.”

Lepe added to that laundry list good access to area airports and freeways. “It’s close to Sand Hill Road without being right next door, where you would have to run into venture capitalists every day,” he quipped.

David Lieb and Jake Mintz dropped out of business school at the University of Chicago and moved to Mountain View in 2009 after founding Bump Technologies, which lets people exchange contact information, photos and other digital data simply by knocking their smartphones together.

The fast-growing startup — Bump says it adds up to 150,000 new users a day — recently outgrew its digs near Y Combinator, and Lieb acknowledged the allure of San Francisco. But, he said, “We still see incredible talent in the valley.” To make life easier for employees who live in the City by the Bay, he and his co-founders picked new offices near Mountain View’s Caltrain station.

To be sure, Mountain View doesn’t have exclusive rights to the startup picture. Plug and Play Tech Center, for instance, houses nearly 400 of them at incubators in Sunnyvale, Palo Alto and Redwood City. Palo Alto officials, for their part, say they don’t track the number of startups in their city.

Still, compared to some of its competitors, Mountain View has “always had a little bit of a homier feel,” said Nick Chaput, who opened coffee shop Dana Street Roasting Co. during the dot-com boom. After weathering the bust and two recessions, he sees neighboring buildings once more filled with new tech firms.

“It’s nice to have Atherton or Woodside as your home address,” Chaput said. “It’s nice to have Mountain View as your business address.”

While Mountain View officials likewise don’t keep a tally of how many startups are in town, Tiffany Chew of the city’s economic development office said there are more than 100 in less than one square mile of downtown alone.

“We try to make ourselves accessible to the startup and tech industry,” she said. That includes attending startup events, introducing startups to local landlords and real estate brokers and walking entrepreneurs through the planning and building process.

“We want to let them know we’re supportive,” Chew said. “The city has become a niche for these kinds of companies.”

Officials in San Jose say they also work to help startups find office space and employees, clear permitting hurdles and make connections to potential partners and customers. Yet they concede that budget travails can limit other outreach efforts.

And the City Council is currently embroiled in controversy over a newly unearthed report that concluded San Jose’s tech incubators, despite receiving $30 million from taxpayers over the past two decades, have generated few jobs — partly because most of those startups didn’t stay in town.

Mountain View, too, faces the challenge of keeping fledglings from flying the coop.

Jessica Livingston, another Y Combinator co-founder (and Graham’s wife), said many entrepreneurs her group backs eventually head to San Francisco. The South of Market neighborhood there is so startup-crammed that it’s a flashback to the dot-com era.

Lepe acknowledged that as Ooyala looks to more than double its payroll to 500 in the next couple of years, “We may require more square footage than Mountain View can support.”

Travis Biziorek and Jim Nguyen can only dream for now of that kind of growth. The duo last fall founded Kibin, an online community for people to critique each other’s writing. They just graduated from the 500 Startups program and are seeking seed funding.

But even as they look forward to making their first hires, they’re hoping to keep their workspace at 500 Startups, which is a bit like a fraternity house basement crammed with newbie companies.

“We love it there,” Biziorek said, speaking not just of the incubator but downtown as a whole. “It truly feels like home.”

Contact Peter Delevett at 408-271-3638. Follow him at Twitter.com/mercwiretap.