I rarely (once or twice a year) get a migraine. I haven't figured out what triggers them, but I get really bad tracers, to the point of not being able to see, and light makes me want to puke.

My wife used to get them REALLY badly. I had to take her to the ER on at least two occasions to get a shot. It finally got to the point that I had to practically force her to go to the doctor. It's not normal to get headaches three days a week. I wish I could remember what they did, but they made her change a few things and her migraines have gotten more rare.

EDIT: There was an interesting interview on NPR with a woman who did intensive studies on migraines.