Any one of Berkeley, Emeryville, or Oakland would be great!

In Berkeley there's:

- the new David Bower center (aka The Hub) in downtown

- Caffe Med on Telegraph near campus is pretty spacious

- the 2 story Starbucks on Oxford & Center in downtown

Emeryville is kind of limited:

- Peet's on Bay Street seems roomy

Oakland:

- A'Cuppa Tea on College & Alcatraz is bigger than the average local coffee shop, open late, and has free Wifi

I'd also be happy to put you in touch with someone in Startup @ Berkeley for more help and ideas.