My specialty is the ED and I have been there for about 5 years, now. I started out in cardiac (which I liked a lot) but after a couple of years, I felt it was time for a change - I felt like I was missing something since the ED always seemed to spark my curiosity.
I finally was given the opportunity when a small rural hospital had an RN position in the ED available. I loved it right from the beginning. I knew that the ED was where I belonged. I can easily say that I never truly felt comfortable on the cardiac floor but in the ED, I felt at "home."
I guess what I love about it is that you never know what you're going to see or treat. It could be the simplest complaint like a splinter to a full-blown cardiac resuscitation in progress (usually both in the ED at the same time). I feel that the ED utilizes all of my clinicals from nursing school since we see it all (peds, med-surg, ortho, psych, ob-gyn, etc.). You have to be on top of your game and be ready for the unexpected. You also have to have great critical thinking skills as well as a great sense of humor. Also, being able to improvise and multi-task are important, too. Your shift can have a down-time where it seems like nothing is going on and then, all of sudden, patients and ambulances just seem to never stop coming through the doors.
Finally, I think the thing that I love most about the ED is the true sense of teamwork and comraderie among the staff. I never had such great working relationships with other nurses, doctors, and nursing assistants as I do in the ED.
Hope this helps with your question.