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Limiting the list to Santa Monica proper is tough but I'll try to include some ideas that should be near by at least. It might also be worth noting the particular strengths and weaknesses of the area. In my opinion the westside does very well with: Persian, Japanese, Oaxacan, and Italian. Asian food (Japanese withstanding) is a major weakness of the area, it breaks my heart to say.
Also, despite eliminating Japanese from your rec request I can't resist a couple.
I strongly second the recommendation for Santouka. Their shio broth is very rich and their noodles are superb. It's the best ramen I've had outside of the South Bay and it's not even close.
I'd add Torofuku. Concentrate on the rice dishes as those are their specialty.
Monte Alban is indeed superb but I'd also throw some support to El Super Taco in the same pod mall. In particular, try their clayudas (sometimes spelled tlayudas). They fold theirs in half and then chargrill it. It's different from the style I'm used to and I think it's quite good.
Guelaguetza is excellent for Oaxacan, too. Montel Alban seems more popular these days on this board but they are different and I think both are worthy of good marks. If you find you like Oaxacan food, also try El Texate. I find them hit or miss regarding the food but they always make great drinks so it' s fun with friends. I seem in the minority on this one but I really like Tlapazole. It's a Oaxacan inspired bistro with an excellent tequila selection.
There are quite a few options for Persian. I think Javan and Flame deserve to top that list and I'd kill to know where there is better in the city.
Poom Thai is the only Thai restaurant I can stand in the area. It'll work for delivery if you have a craving but I hesitate to call if very good.
I'd place VIP Harbor in that same category for Chinese food. The best that can be done when you just need Chinese and you can't drive far (or at all). They also have dim sum on weekend mornings so that's nice I suppose.
Le Saigon is actually okay for Vietnamese. They have a limited menu and it can't hold a candle to the stretch of paradise on Bolsa Ave. but it isn't bad. It's good for a change of pace.
There isn't a full service Armenian restaurant in the area that I know about but Zankou Chicken is on Sepulveda. Pick up a roasted chicken or two on the way home and plenty of the garlic paste.
In a pod mall on Westwood just north of Santa Monica you'll find Sunnin serving up some solid Lebanese. They mainly do mezze.
Right next door in the same mall is Ambala Dhaba. I think they do the best Indian near SM. I'd recommend the channa masala with an onion kulcha in particular. Many like Bombay Cafe on Pico. I must confess that I like Pradeep's on Montana. I can forgive many of it's failures because they are really trying to do a light and healthy take on Indian. Going in there with the proper expectations are crucial.
If you're willing to travel just a bit you'll find an excellent Southern Indian restaurant serving vegetarian food called Annapurna's Cuisine. Wonderful Dosas! This is probably the best Indian on the westside as a whole. Mayura is also down he same street and they do kerali-style and they are worth trying.
Back to that pod mall on Westwood. There is Ramayani for Indonesian food and I've had some good meals there.
Let us know what you think and any new finds you come across.
You've mentioned, "Santa Monica," in your request, but a good handful of responses are out of Santa Monica-proper, which is fine since all are easily within striking distance of each other given you have a car. If you include Mar Vista, you may want to put Gallegos Mexican Deli and the Mitsuwa food court on your list as well. They're both at or close to the intersection of Centinela and Venice.
Gallegos Deli's roots are deep in Santa Monica from over 60 years back at their original 14th Street location and are known for their barbacoa, tamales, enchiladas, soups, and chips/salsas.
The Mitsuwa food court is primarily known for killer noodles - Santouka ramen and Sanuki Sando udon. But the China Table Tokyo Hanten is quite good as well. It's Chinese and American cuisine interpreted through the Japanese kitchen. Probably the most popular dish there is the "Hamburg and gyoza" combo. The set with two hamburg patties can easily feed two.
Gallegos Mexican Deli
12470 Venice Blvd, Los Angeles, CA 90066
3760 S Centinela Ave, Los Angeles, CA
What I meant by ethnic is Ethiopian, Lebanese, Persian, Indian, Armenian...not Japanese or Italian...like really different stuff. I've eaten at that Indian restaurant on Pico and like 26th which is just OK. I am from NYC where we have everything- and most of everything is GREAT.What is the Indian next to the continental shop? What is the name of the Ukranian grocery store?
No Lebanese in Santa Monica, but Sunnin is just down the road in Westwood. Tons of Persian in West LA, just run a search on the board. I think that branch of Akbar that you've eaten at is closed, which is no real loss since it wasn't good. I like Nawab for Indian at Wilshire and 17th. The Ukrainian store is called Ukraina Deli and carries Russian, Ukrainian and Armenian food. Also, you really should try Musha if you haven't.
Three Square in venice has a bunch of Austrian/German dishes
There is a Ukranian grocery store on Wilshire in Santa Monica
I suppose you could call Bay Cities Deli an ethnic place, but it's a stretch. The food is good, though.
Tacos Por Favor, La Playita, and the taco trucks on Rose and Lincoln in Venice for Mexican food.
Monte Alban is the best ethnic option in Santa Monica
You're a short drive from Sawtelle in West LA, which is all Japanese.