The only department I have ever worked in is telemetry. It's constantly busy, demanding, and the duties for PCTs are somewhat specialized. For example, doing ECGs and sheath pulls after heart caths. I have learend a lot on this unit. I enjoy working telemetry, because floating to any other floor is a piece of cake. Don't apply for a tele position if you don't want a challenge!
Medical/Surgical ICU and the emergency department. Both units are very fast paced, and each one requires a lot of hard work and skill, but they are incredibly fun. I like the emergency department because you never know what might come in on any given night, but I like the ICU because you have more quality time to spend with your patient and their family. Each unit has its pros and cons, but I enjoy both.
I'm in the float pool at my hospital now (started out on telemetry, transfered to a monitor tech job, transfered to cardiovascular tech job, going back to the floor as a floater since I'm starting school and need the schedule flexibility) and my favorite, by a looooooong shot, is ICU. Second is ER, third is NICU. Then GI/endoscopy lab, mother/baby, psych, peds, tele, and general med/surg is last. Boooooring.
I work at a critical care unit (ICU-step down) that focuses on the neuro population. Its a very heavy floor to work on. Pt. post surgery are mostly confused with slurred speech, incontinent of both bowl and bladder. They often require restraints becuase they try to pull out indwelling caths, NG or G tubes. We get alot of DNR's post op becuase of poor prognosis. Not all the cases are like this, but most of them are. If I were you, and had a choice I would go for like an MICU or CCU floor becuase then the RN's have less pt's, and its just a whole lot less stresfull.