Chill and laid back... definitely Psych, Anesthesiologists, and PM&R... no doubt.
Now, I know a lot of EPs... and most of them are chill in the sense that they're not douchebags like some surgeons. But they are usually ADHD types... very sociable, like to keep busy and moving.
Also... ortho's are NOT laid back... in general they're high strung and worrying about getting in that ACL before tee time.
I've been doing some thinking on medical specialties now that I've been getting interviews... it seems like Anesthesiology offers me a plethora of opportunities. I can be an expert in physiology and pharmacology. I get to be in the OR, and I can work in an ICU if I do so please. Then there's the added benefit of doing pain management. And honestly, alleviating pain is something that many people require desperately... let the internists figure out the root cause of the pain. I can make a decent living, afford to send my kids to good schools, take a nice vacation here and there. And support my science fiction habits... comic con etc. Plus I can watch my kids soccer game on the weekend... needless to say any specialty can afford you this type of lifestyle if you play it smart. But to me it seems people in gas love their lives.