Lately all the restaurants that I'm excited about in the Larkin Street corridor are Thai. There's the much loved Lers Ros (which remains better than the new Hayes Valley location), Zen Yai's boat noodles (which DezzerSF said is the best version ever: http://www.chow.com/digest/119078/boa...), and now the new (to me, but I think also new) Jarin Thai Cuisine.
Jarin is a mom-and-pop shop with some interesting choices on the menu, which is less comprehensive and risk-taking than Lers Ros, but includes some solid and well prepared choices beyond the predictable and over-sweet noodles and curries of poorer quality Thai restaurants.
Of what I ordered, I liked the Moo Ma Now best. A chili-spiked pork salad with lime-cilantro dressing, it hit the right balance between sweet, tart and spicy, with a funky baseline note from nam pla. Good quality pork with no extra flab or gristle.
The restaurant is pretty and well kept, with a a blue-painted ceiling and decorative wood carvings. The husband was my waiter and both he and his wife appeared to do the cooking; their daughter helped out, too. Warm, friendly service, if a bit conservative with recommendations (e.g. "Try the pad thai" "Kids like pad thai").
A cabbie stopped in and ordered spicy cabbage to go--didn't see that on the menu, but I want it next time. They take credit cards. I don't think they deliver, but seemed to have a brisk to-go business. A selection of beers displayed behind the counter, but I didn't look too closely at them.
Jarin Thai Cuisine
807 Ellis (between Polk and Van Ness)