As far as intellectual stimulation goes any and all fields are. All depends on how much you enjoy reading and employing what you've studied into your management decisions.
All of those fields are good decisions so worst case scenerio is you should be fine.
ER: (-) Too much primary care poop and nonsense complaints for me. You also must be comfortable with dealing with those on the periphery of society such as: crashing GOMERS from dialysis centers & Drug seeking chronic pancreatitis regulars....plus side you can boot em upstairs to IM =).
(+) Most of the EM residents I've met are by far the most social people around and that makes work all the more enjoyable. This was the most attractive aspect of the field to me. Procedures/trauma are a plus for sure but when you are juggling multiple rooms they can be a pain. +++++SHIFT WORK & and you can "save the day" sometimes.
RADS: I don't have much exposure to the field so I cannot confidently present the +/-'s for ya. However, from what I have seen its great to not have to deal with all the social BS on the floors....a major relief. Outside of that you just have to be comfortable with limited pt contact and being a signature at the bottom of a transcription vs. being a face (unless you're doing IR which is a great field). If you can do that you're set.
In addition I don't think rads is cush by any stretch of the imagination. Those guys are damn busy. Radiologists get plenty of calls concerning their readings for management decisions. In that sense its definitely not complete isolation from the rest of the docs in house.
Anesthesia: Just check the FAQ and do a search of "why anesthesiology." If you decide that you enjoy it/find it the most tolerable field then you have to be comfortable with the fact that you will be largely unrecognized in your career. If you go into pain or CC its a different story I suppose. For me I couldn't friggen care less.
