I bought my house 7 years ago, and the choices at the time were an ARM at 4.5 or a fixed at 6.5, based on all the information the ARM was the better choice - and I clearly made the right decision, in those 7 years, it went up once to 5.5 percent and has gone down every year since.
It can only go up 1 pt a year and only 2 pts in 5 years. Even if I kept this house for 10 more years the highest rate it would be at is 5.5.
I took the advice of many people and there is clearly tons of bad information out there on ARM's, my ARM was the right choice for me and I can say that for sure.