materialism!

Dennis discovered a Thomas the Train brochure in a drawer today. It lists all the trains and play sets that are available for purchase. He studied it for a long time, carrying it around with him, and he finally brought it to me and pointed out each train and said "I would like to get this train for Christmas" and "Can I have this one for Christmas, too?" and "I sure would like to get this set for Christmas, Mommy". He would ask me "what does this say?" and I would reply with, say, 'Trevor' if that was the name of the train he was pointing to, and he would say "I sure I hope I get Trevor for Christmas." I tried to use this to my advantage and tell him that he needed to start being good if he wanted all that stuff for Christmas. It didn't work so much. This week we're having fits of flagrant disobedience, something we're not used to from Dennis. He screams "NO" and pushes us when we tell him it's bedtime. He whines and cries when we tell him to do something. He yells "NO!" when we tell him to go to Time Out. We are shocked and trying to come up with alternate parenting strategies where we aren't angry and yelling back at him all the time. Surely it's a phase, and let's hope it's a short one!