Everyone has made some really great points, and I think you need to find what works for you. One thing that has helped me is to have a picture of what I want to look like after, and I had a picture taken of what I look like now. Only by looking at pictures did it really hit me how much weight I had gained. So every day, I look at the picture of me when I was thin, and that contributes to my motivation -- that I want to look like that again.
I have also bought a couple of articles of clothing that are a size or two too small (at least right now they are). I did this before, and it felt so good to be able to actually wear something I bought to work that didn't fit before!
I also try to read or look at something every day that serves as a reminder and motivation to lose. For example, the plan I am following comes with a book, so every night before I go to bed, I read a chapter. Coming here and reading the threads helps too, and I have subscribed to a couple of health magazines. Even though I know what I need to do to lose the weight and I am very aware of what is good and bad for me, I need some kind of visual reminder, DAILY!