I am going to focus on gospels included in Ehrman's collection. Primarily I want to give you a summary of them, in case you haven't encountered them and would like to read them yourself. Many of them can be found online, though I do strongly suggest picking up Ehrman's book. I also give some of my own commentary in the process. I have skipped a few of the more heavily fragmented gospels and the ones about which I have nothing much to say.
This book doesn't contain stories, just teachings of Jesus. It's more like a book by Confucius or Lao-Tzu. While many of the teachings and sayings are found in the four canonical gospels, their significance seems illuminated more greatly here.
The Gospel of Thomas demonstrates (even more than usual) that Jesus (a) spoke almost entirely in metaphor (when he wasn't speaking in parables) and (b) that one of the major metaphors was the Kingdom of God, which signifies not a literal place but a state of mind. God himself is a metaphor as well. For example: "When you come to know yourselves... you will realize that it is you who are the sons of the living father."
Life and death are also metaphor. Jesus says, first thing, "Whoever finds the interpretation of these sayings will not experience death." He isn't referring to literal, bodily death, but to a recognition of a greater life, of one that has always and will always exist. Or, as he later typifies it, the "light." He tells his disciples that they "came from the light, the place where light came into being on its own accord and established itself and became manifest through their image."
Joseph Campbell once explained the above concept through a metaphor of a light bulb. When a bulb burns out, you don't say, "Well, no more light for me." You simply replace the bulb. The light is "manifest" through the bulb, which is yourself, so when it's your time to shine, shine as bright as you can. And when you burn out, that's just the end of your body, but not the light, which is (as Jesus says in this gospel) where you came from. (This might also bring new meaning to God's phrase "Let there be light.")
Another key message in Thomas is that what you're looking for (literally) is already here (spiritually, inside you). After the disciples ask when the new world will come, Jesus says, "What you look forward to has already come, but you do not recognize it."
A final passage worth noting is about Mary and women. When the disciples say that Mary Magdalene needs to leave the company because she isn't "worthy of life," Jesus says, "I myself shall lead her in order to make her male, so that she too may become a living spirit resembling you males. For every woman who will make herself male will enter the kingdom of heaven." It sounds backward at first, but it's feminist in a figurative sort of way, simply saying that women will have the same privileges as men.