Gosh SGV has tons.
Happy Family is a staple lunch for me. I go to the one on Atlantic. Nice new place, good and fast service. Food is the exact same in all the branches of this restaurant chain, but I like the execution at this particular location, the food just seems a tad better somehow. The view is kind of nice too, if you like a view of whizzing cars. I love the nice new digs too. The old place was dingy, but the new location is in a swanky new mall. I like.
Gourmet Vegetarian is the one you're thinking of in Focus Plaza. I really like that place for the atmosphere. Food isn't bad either, not great imho, but not bad, but then I've only tried about 10 dishes.
If you like Taiwanese food, and you are not vegan, you can try Sweet Veggie. That's off Fullerton Rd, off the 60, a little east of the SGV. Very cheap and nice boxed lunches. The BBQ "pork" stunned my co-workers because they were hoping I had changed my ways and started eating meat. Most items are vegan and they specify which have egg, milk, peanuts, or are spicy. That said, I can't eat egg, and I've gotten a reaction each time I ate here, so I can't really do this place. That's a shame because their mapo tofu has lots of schezuan peppercorn action, and it's overall the best non-homemade vegetarian version I've had so far (which unfortunately isn't saying much). I love the food here. I wish I could eat here. They have stinky tofu and it's pretty damn stinky, like a block of manure in your mouth. Not for the faint of heart.
New Happy Family in Rosemead has good lunch specials too. I don't like them because they don't have brown rice. That said, I'd still come back, as their food is quite good, and the lunch specials are reasonably priced.
There are a bunch of others, but these are the ones I'm liking at the moment.
The information in this thread should be pretty current:
(the chef at the place on Las Tunas used to work at the one in Focus Plaza, and the food / menu is similar).
Happy Veggie Garden in Rowland Heights is pretty good.
I have a long list in this post, but it's old, so some of the places may have closed or gone downhill.
While it doesn't have ratings, this page is usually pretty up to date and complete; you can search on this board or elsewhere for opinions on specific places.
I like Bean Sprouts in Arcadia, though some stuff is better than others, and certain things are a bit on the bland side.
If you're looking for vegetarian (but not Buddhist vegetarian) food at non vegetarian restaurants, these threads have some useful information, though some of the places mentioned may have closed etc..
Now that Vegetarian Wok is gone, Happy Veggie Garden takes the top spot in this category for us. My mom is a vegetarian so we're quite familiar with most of the Chinese vegetarian places. Bean Sprouts can be kind of bland and my mom thinks it's too expensive.
Supreme Vegetarian Cuisine is the place on Las Tunas that will47 mentioned and I believe there have been a few chef changes. The food isn't bad but the service has rubbed us the wrong way sometimes.
Happy Veggie Garden is a lunchtime staple for me. There's this one waitress that looks kind of mean and crotchety, but she's really not. Her English just sucks (bigtime).
In that same mall, there's a place that sells cute knockoff handbags for $10 each. I bought a red one that my co-workers really liked. Unfortunately, they don't last long, but neither does my interest in a particular purse.