As a new grad, I went straight into ICU. I've never had any doubts that its what I wanted.
I worked in EMS for 3 years prior to being a nurse. Working EMS, I already know exactly what comes through the ED. The appealing side of the ED is that you don't have to neccessarily be with the same aggrevating patient for your entire shift. But it also doesn't mean you won't deal with several jerks throughout your shift. My EMS experience told me that I know how many of the people come through for absolute BS, which that sort of thing leaves me banging my head against a wall. For me personally, I probably would've burnt out very easily in the ED. Another appealing thing about the ED is that there are many things you don't have to worry about. You might get your patient's food, but you're not worring with meal carts and trays, at least not as much. You're not worried about if they've been bathed unless they need a clean up. You're not as worried about turning them and doing mouth care every 2 hours, etc. And your documentation is a little more streamlined and focused.
I work in a medical ICU at a level 1 trauma teaching hospital. I see all sorts of really complex patients, and of course we always get overflow from other ICUs. So I still get plenty of trauma patients etc. And in all honesty, I only find trauma patients to be fun out in the field or in the ED. I hate trauma patients once they've made it upstairs, but that's beside the point. I always have two ICU teams available to me, always sitting on the unit unless they're off the unit to see someone in the ED or a patient crumping on the floor. We have a huge amount of trust between our docs and nurses, which gives us a lot of autonomy, and they listen to our suggestions and take our concerns seriously. I feel like there is a lot more to learn in the ICU. I like to just have my 2 patients (or sometimes 1:1). Downside to that is that sometimes I hate having to be responsible for EVERY human need of those 2 patients... lol. Sometimes it sucks to have a patient who can't turn themselves or anything, and so they're sitting in poop, thristy because they're NPO, and need to be turned, but they have to wait a few minutes because you're trying to keep your other patient alive.
Anyways, I think I went on a tangent. I have a really good friend who is an ED nurse. We get together and talk shop often. We share stories and discuss what we like and dislike about our specialty and how it compares to the other. She loves the ED, and I love the ICU. I will say though, she has said that working in the ED has made her feel like she has lost some skills, and often get disconnected from hospital policies and procedures since they don't really apply in the ED.
Its really all a matter of personal style.