I can not imagine working in any other specialty except Emergency Medicine. During medical school, however, I was torn between various specialties. These included Vascular Surgery (had an inspiring attending on-service and the VA patients were hilarious) and Interventional Radiology. Fortunately, I saw the light.
I am curious, as a medical student, what specialties were you considering before deciding on EM? It would be interesting to see if there were a trend.