If you're looking for organic stuff, Amy's Kitchen makes a whole line of frozen organic vegetarian meals and foods that are really good. Not all of this stuff is necessarily very healthy, but certain items (ones without a lot of cheese) can be pretty good from the health side. They use a lot of spinach which is nice if you can bear eating frozen spinach.

I just keep a cooler in my trunk and throw one of those blue ice things in with whatever food I want for the day. It works well enough so that lunch foo will keep fine for a few hours.

THREE CHEERS FOR HUMMUS.