Looking for donburi on the Peninsula
A recent mention of egg foo yung (in the "Americanized Chinese" post), followed by a mention of donburi, had me think: hey, where's a good place for donburi around here? I work on the Palo Alto/Mountain View border right off 101, so I have a lot of latitude in where I can get to for lunch. (I've been known to go at least as far as Burlingame.)
I was literally just sitting at my desk having a major donburi craving (seriously) and went to look for recipes online... then thought I should just go to a restaurant for it. So I logged onto Chowhound. Your blog was the first thing I saw when I logged in. I got a little freaked out that big brother was really watching me but am chocking it up to strange coincidence. Anyhow, I don't know of a place in the peninsula for donburi but I just had to share my strange experience. I think I'll head to J-Town in the city for my donburi fix. Good luck finding yours.
Being in the Peninsula you have TONS of options.
For the definitive oyako-don, Sumika in Los Altos is the answer. Can't beat chicken and eggs sourced to Petaluma Farms for free range organic chicken (and doesn't get any better than this) along with a full bodied flavor that matches the best of Japan and excellent Japanese restaurants in Hong Kong. Unfortunately they're open dinner only but a friend told me they will soon open for lunch with a limited menu, and the rumor is oyako-don will be served.
Your 2nd option is Hattoriya off 101 on San Antonio. Pretty decent and you won't have to drive into Gombei (though their donburi is quite decent, and great grill flavor). Oyako don here is a far cry from Sumika's, a notch or two below Gombei, but it is arguably the closest for you.
Gombei is a safe recommendation and will have a wider variety for you to choose from.
If you are willing to drive further, may I suggest Gochi and/or Saizo (Cupertino and Sunnyvale respectively) for even more authentic and delicious fare that tastes exactly like it should. If unagi don is your craving, Saizo's grilled unagi over rice (with unagi liver) is superb, a tad bit salty, though that set lunch includes a flavorful miso soup that blows away the instant crud served at many lower end places. Gochi's gyu-don lunch portion is a bit modest but very authentic (the raw egg over the meat gives it another dimension).
Saizo is definitely underrated for lunch. Both places are sadly cash only (for lunch).
Sashimi don such as tekka, hamachi, mix or chirashi, well I suppose go to your favorite sushi/Japanese restaurant.
Nami nami in downtown Mountain View on Castro might be worth looking into, though I don't think they serve actual donburi (but lunch sets with rice).