Grad School - Science or Engineering?

I'm looking to go to grad school soon, and I'm trying to gather as much data as possible about my options. One interesting question for me has arose: should I pursue a science or engineering based course of study.

This seems to be more of a philosophical decision to make, contingent on my own personality and interests. However I am up in the air about this as I believe I could be happy going either route.

I would love to hear from others who have made a similar decision or have a well-reasoned opinion on the matter.