Raw almonds are healthy, tasty and provide substance/energy. Granola bars (healthy and not) are great when everything is going wrong and you need to eat something. Cheese and crackers are standard.
For night passages, I find that it depends on the trip (warm or cold, rough or smooth) as to eating sweets or savories so I try to have both cookies and chocolate and nuts, as well as hard boild eggs, salami and cheese. Not super healthy, but not a regular occurrence, and very satisfying.
Homemade muffins taste great, too, and are fairly easy to make even underway.