I have had much success with 5/1 mortgages. Like you, I knew that I would be moving within 5 years. However, financing these past couple of years at a one year ARM is not wise.
Very very few people should be getting short term (1 and 3 year)ARMs right now. Fixed is prefered, but if a nice spread can be obtained with a 10/1 or 7/1 I would have no hesitation about putting someone in one of those. Especially first time buyers. They won't be in the home that long.