I, too, really enjoyed my neurology rotations both as a medical student and a resident. It's also true that there is heavy overlap between the fields. You'll find that the information you learn in neurology will, perhaps moreso than in other medicine subspecialty rotations, be incredibly useful when you're seeing patients later on. As I mentioned in a previous thread, there is particular overlap between the seizure disorders and psychiatric illness...at least from a personality standpoint.
Some cool reading:
Blumer, Dietrich. Evidence supporting the temporal lobe epilepsy personality syndrome. Devinsky, Orvin. American Academy of Neurology
Volume 53 (5) Supplement 2, 22 Sept. 1999, pp S9-S12
Devinsky, Orvin. Evidence against the existence of a temporal lobe epilepsy personality syndrome. American Academy of Neurology
Volume 53 (5) Supplement 2, 22 Sept. 1999, pp S13-S25
Plus, having this type of real medical knowledge helps you to much better understand the full aspect of patient care, answer their myriad questions, and treat them in a much more comprehensive manner than would otherwise be possible after you've had that kind of hands-on neurological exam and theoretical basis with treatment experience.
You'll be performing basic neuro exams on all your psych admits...I think that's pretty standard. While you might skimp when you're short on time, your internal alarm will go off when you sense something is "not quite right" with the way a patient is walking, speaking, etc that will prompt you to do a thorough exam and often, pick up findings that can be addressed.
