Peanut butter and banana/organic or homemade jelly always works.
My husband never gets tired of those. He also likes chickpea salad sandwiches or macaroni salad with chickpeas/celery/onion/vegan mayo. The macaroni salad can be made in a huge batch and stored in the refrigerator and packed for work several times. It tastes better cold anyway. Another one is to make potato salad ahead. My husband LOVES anything potato. I make it the old fashioned way for him, with vegan mayo (he likes Just Mayo better than egg based mayo), mustard, vinegar, potatoes, onion, salt/pepper etc.
I second the veggie burgers also. And Amy's makes frozen burritos and other ready made vegan meals, though that can get expensive. I sometimes make a huge batch of my own homemade veggie burgers and freeze them for easy meals later. I also like to make my own energy bars and freeze those for future use. My husband and I enjoy those when out on the trail. I use this formula:
Hummus and crackers is another one. I can even get my SAD junk food husband to eat a garden salad if I use hummus or a thai peanut sauce as the dressing and throw in some seeds, raisins, chickpeas and other hardy items along with veggies and leafy greens.
He also likes canned Chow Mein vegetables and chickpeas or cubed tempeh over rice (though for him it has to be white rice...sighs) with an Asian sauce (molasses, soy sauce, ginger, rice vinegar, water). He used to hate tofu but he likes it if I cube up some extra firm tofu and saute it with red pepper, snowpeas, onion, broccoli, raisins, a little oil, and have this over rice or couscous with a peanut thai sauce. The key is always the sauce.