I took a medical specialty aptitude test on the University of Virginia's website, and here are the results. You answer 130 questions about your personality, the way you are, the way you like to handle things, etc., and it pops out a long list of medical specialties for you. I have no idea if anyone places any stock in this sort of test.

Rank	Specialty	Score
1	plastic surgery	45
2	general surgery	44
3	radiology	44
4	urology	44
5	nephrology	44
6	gastroenterology	43
7	thoracic surgery	43
8	occupational med	43
9	otolaryngology	43
10	orthopaedic surgery	43
11	pathology	42
12	nuclear med	42
13	dermatology	42
14	colon & rectal surgery	42
15	radiation oncology	42
16	anesthesiology	41
17	pulmonology	41
18	hematology	41
19	neurosurgery	41
20	obstetrics/gynecology	41
21	physical med & rehabilitation	41
22	ophthalmology	40
23	neurology	40
24	aerospace med	40
25	rheumatology	40
26	endocrinology	40
27	infectious disease	40
28	allergy & immunology	39
29	cardiology	39
30	psychiatry	39
31	preventive med	39
32	pediatrics	38
33	med oncology	38
34	general internal med	37
35	emergency med	36
36	family practice	35