Running Mania

So the past two days I have been thinking non-stop about my action plan for my running and marathon training. I can't get enough of online articles, Runner's world magazine, and searching through every gadget and supplement I can find. But, I am no expert. I have never run a full marathon, have not been faced with a mental breakdown miles from the end, and haven't put my body through more than a half marathon run. But for me, I am all about the details. I want to be prepared, with the right nutrition and the right "swag". So, asking those out there who may have done distance races or events, what are your top things to have, and what have you found to work or not? I would love some responses or books/articles that would point me in the right direction. I am a little less than 16 weeks out, and so excited! I also have about another 20 pounds to lose for my ideal race weight, and the goal of the day was to avoid any and all cookies/cakes/sweets. So far so good. The oatmeal chocolate chip cookies sitting on my counter haven't been touched. I raced my half in January at the weight I am currently, but my knees were in so much pain the days following, that getting a lighter load on my body seems like the best idea I have.