What do you eat at home?
Mix of both definitely.
Breakfast is usually Western (i.e. orange juice, toast, coffee, eggs on the weekends.) Lunch is a mix (I don't bring a bento to work, so I usually go out to eat, and that can be anything, really.) Dinner is a mix. I'd say probably 5 nights of the week would be washoku (rice, miso soup, some kind of main dish, sides of veggies) 2 nights of the week would be not Japanese.
Mix of both, but mainly non-Japanese food. I'll usually have a breakfast of granola + yogurt or toast and a fruit, lunch on weekdays is school lunch, which can vary from miso soup, a grilled piece of fish, pickles, and white rice to a piece of pizza bread with strawberry ice cream on the side.
For dinner, I've taken it upon myself to introduce my girlfriend's family to western dishes. They're extremely fond of quesadillas, meatloaf, macaroni and cheese and simple, hearty foods of that nature. Nachos were also a big hit.
I find cooking for myself to be a by-the-seat-of-my-pants adventure, since many times ingredients are not readily available in my country city of 34,000. Cheese is horridly expensive (maybe 500 yen for 100 grams of plain cheddar), and the majority of items are tailored to the Japanese diet (as is expected). That said, I'll still throw together some pasta or a nice sandwich when I have a chance to enjoy what I miss from living in the States.
I also do a mix of both.
I make onigiri pretty much every day, so there's always a little Japanese food mixed into my daily menu. When I cook Japanese, it's usually home style dishes that I never knew about until moving to Japan. Dishes like oyakodon (chicken and egg over rice), nimono, yakiudon and nabe are so easy to prepare, can be made in big batches so I can have leftovers for lunch at work, and the ingredients are usually already in my fridge.
I don't have an oven, so that eliminates a lot of western food that I liked to make in The States. I desperately miss Mexican food, so I have experimented with tortilla making and sometimes whip up fajitas or burritos. I make homemade marinara sauce about twice a month, sometimes with meatballs using panko as breadcrumbs.
Sometimes I have rice and pickles for breakfast and sometimes I have yogurt, granola and a banana. It just depends on my mood.