Back before I had children, I promised I would never have a Party City themed party. My kids would have all DIY themed shabby chic parties. They would never want a party based off a television show.
Yea right.
Almost five years in, and I go with whatever my kids are most obsessed with at that time. It makes all the party planning effort worth it when their eyes pop open watching their home turn into a giant replica/wonderland of whatever they happen to be most into.
Voila my train obsessed toddler's train birthday party. Totally worth it.