Orange Co foodie tips
The areas you mention are essentially devoid of ethnic cuisine, and Aliso Viejo barely has anything at all (there's a Native Foods and an Original Pancake House). In Laguna Beach there's more stuff. Broadway by Amar Santana, Three Seventy Common, House of Big Fish and Ice Cold Beer, Watermarc, 230 Forest, Eva's Caribbean Kitchen, and Alessa.
For high-end you have Studio at the Montage, San Shi Go, and Raya at the Ritz.
Inland a little bit is Sol del Sur (San Juan Capistrano) and Break of Dawn (Laguna Hills), or head a little further north and east to Lake Forest and Irvine for ethnic food, especially Asian.
re: Das Ubergeek
To expand on Dan's recommendations, Break of Dawn is a board favorite for breakfast and lunch. San Shi Go is my favorite sushi spot (the one in Newport, not Laguna). House of Big Fish (I can't seem to get a link here, it is in Laguna) is casual and busy, but another board favorite.
Bluefin is another excellent sushi spot. K'ya and the rooftop bar at the same hotel are worth visiting. The Side Door and Crow Bar are good gastro pubs.
As was mentioned, Asian options really open up if you head inland. Irvine has a large Chinese population, and Garden Grove is home to Little Saigon.
7952 E Pacific Coast Hwy, Newport Beach, CA 92660
Break of Dawn
24351 Avenida De La Carlota Ste N6, Laguna Hills, CA 92653
Crow Bar & Kitchen
2325 E Coast Hwy, Corona Del Mar, CA 92625
San Shi Go Sushi and Asian Cuisine
205 Main St, Newport Beach, CA 92661
K'ya Bistro - Laguna Beach
1287 South Coast Highway, Laguna Beach, CA 92651
3801 East Coast Hwy, Newport Beach, CA 92625
The only Sichuan place—and I mean real Sichuan, not fake New York City "Szechwan"—I could recommend in Irvine is Chong Qing Mei Wei, in the same building as the 99 Ranch on Walnut just north of Jeffrey. I specifically recommend AGAINST Spicy City (a branch of the Yunchuan Garden group, or so it seems from the Chinese name of the place), because the chefs are careless about cutting the food and it does not taste right.
As far as pho in Garden Grove and Westminster, my personal favourite is Pho 86 on the southeastern corner of Brookhurst and Hazard. In the same plaza, but closer to the corner, is Pho Thanh Lich, also excellent, and where a bowl of pho costs $2.99 at dinner time (higher for breakfast and lunch).
For bún dishes I recommend Vien Dong on Brookhurst near 13th in Garden Grove.
A couple of good Vietnamese options are Brodard Restaurant - no frills Vietnamese with lots of good options, and Brodard Chateau - a more upscale options with leans heavier of the french influences in Vietnamese cuisine. Another excellent no frills option is Trieu Chau. They get very crowded at peak times, but i love the duck.
Since we are getting out of the Beach areas, Honda-ya in Tustin is a great place for pub style Japanese fare, and they are open until 2:00, a rarity in OC. In Westminster you have my favorite yakatori spot, Shin-Sen-Gumi, on Brookhurst in Fountain Valley.
Shin Sen Gumi Hakata Ramen
18315 Brookhurst St, Fountain Valley, CA 92708
9892 Westminster Ave, Garden Grove, CA 92844
4401 W 1st St, Santa Ana, CA 92703
Honda Ya Japanese Restaurant
556 El Camino Real, Tustin, CA 92780
9100 Trask Ave, Garden Grove, CA 92844