I like Cliff Bars, take them hiking often, but for longer term storage in the car and BOB, I keep Millennium Bars. I initially found out about them because they were packaged in some MRE's I had. I've since seen them from multiple online sources. They have a 5 year shelf life, are foil vacuum packed, and although they are a little dry, they come in many flavors for variety. They have a consistency similar to lifeboat rations.

One source for example is Cheaper Than Dirt:

http://www.cheaperthandirt.net/product/F...CFcQDOgod_j0AfQ