(if you ignore the third installment).
What. The third one was the best. It actually had 3D models and stuff so you could control the camera, and you could walk around the park like a guest (to an extent) and ride the roller coasters. Plus, they had a ton of roller coasters to choose from. It actually looked real. The first and second ones were really good, don't get me wrong, but the third one takes the cake. No reason to hate on it.
Anyway, I absolutely love this series. It's got to be my favorite PC game of all time, especially when you get the animal and water expansion packs. I have all of those expansion packs, but I just can't find the game and I really want to play it after seeing this thread. My best roller coaster ever was called the Fahrenheit (for the record, that was before Hershey Park made the Fahrenheit)