There's a whole slew of restaurants on North Main St. in Walnut Creek (Get off at the North Main Exit, & stay to the right)
Note: This is only the Walnut Creek area

My personal favorite is Vanessa's Bisrto2
(Franco-Vietnamese; Tapas menu & Bar);
http://vanessasbistro2.com/
it's pretty quiet and calm during the day, but at night it gets more lively and you might need to book a table ahead of time (at least an hour). The Calamari is always a favorite there!
There's also Modern China Cafe
http://www.modernchinacafe.com/
They have outdoor seating (be careful of the magnolia tree! the leaves are still falling off!), bar, Dim Sum menu, heat lamps (yay!), the title speaks for itself, it serves a modern twist on most traditional chinese cuisine.

Those are the only two I've actually tried, but you can always check out these:
Kara's Cupcakes (for your sweet tooth) (www.karascupcakes.com/
)Mel's Diner
Sasa (sasawc.com/)
Breads of India (www.breadsofindia.com/
)Erawan Thai Restaurant (erawanthaiwc.com/)
Silk Road Restaurant (www.silkroadwalnutcreek.com/
)Dan's Irish sports Bar (www.dansbar.com/
)Pyramid Alehouse (www.pyramidbrew.com/
)Bombay Indian Restaurant
Tomatina (www.tomatina.com/
)Pomegranate (www.pomegranaterestaurant.com/
)1515 Restaurant (www.1515wc.com/
)Havana (www.havanarestaurant.net/

And that's just to name a few (you can also check out North California Blvd.)