Power bar Harvest bars are definitely tastier than their predecessors, Luna bars are pretty good too. I got some aseptically packaged milk (doesn't require refrigeration) in several flavors recently on sale I plan to try out, 8oz each.
You can get MRE entree's separately along with the heaters if you don't want the whole thing. You can also get other things packaged the same way as the MRE's that can be used with the same heaters. MTR makes some really tasty Indian entree's (all vegetarian I believe). The foil packaging crushes down nice and flat.
http://www.amazon.com/s/qid=1219390055/ref=sr_nr_p_4_0?ie=UTF8&rs=16310241&keywords=mtr&bbn=16310241&rnid=203034011&rh=n%3A16310101%2Cn%3A16310241%2Ck%3Amtr%2Cp%5F4%3AMTR
Tubes of cake icing, not so much. I'd like to find some tubes of yogurt that don't need to be refrigerated though. Jolly ranchers are nice, give you a little sugar, and some flavor to distract you.
Gatorade or similar drink. Really seems to help sip on some of that along with water during the trip.
#1 although slightly bulkier, Fried Chicken. Crackers don't sound so good when you can whip out a chicken leg; trumps any kind of sammich.
BTW - raisins that come loose in the pack, then are unwittingly allowed to 'set up' in a hot car are terribly difficult to remove. From everything.