What airline? Northwest?
If it's Northwest, then you'll be at Terminal 1. The biggest concentration of restaurants will be out in the non-secure area in the middle portion of the terminal on the departure level (4th floor, I think).
As you stroll through that area, you'll basically be walking past one restaurant after another. It's like a shopping/restaurant arcade. And almost every restaurant has a large display window with very realistic-looking plastic models of majority of the menu items. So just look for what looks good, and then try that place.
I can't give you a specific recommendation, because I don't know what you like. But these are the general points I would make:
1). I've probably eaten at more than half of those restaurants in Terminal 1. While I wouldn't say that they're gourmet places, I've enjoyed it each time for what it was.
2). Since you're in Japan, I'd probably go for something you'll have a hard time finding in the U.S. Therefore, if it were me, I wouldn't go for stuff like sushi or tempura at Narita. Instead, I'd think about trying things that look good that you haven't seen before. Remember that a lot of such things are Japanese adaptations of Chinese or Western things that seem un-Japanese, yet you'll only find them in Japan... things like guratan, doria, cream croquette teishoku, hamburg, ebi chili (shrimp in sweet chili sauce... they do have these elsewhere in the world, but I feel Japan's is unique and very tasty). Also you may go for a teishoku (combination meals) that looks really good.
Thanks chowmouse - I'll be in terminal 1 - south wing. I like pretty much all kinds of foods, including Japanese. I've never been to Japan (not that visiting the airport is really going to Japan), so I want to take advantage. I'll take your suggestions and try to go for something more unusual.