You already have had some great advice. It really all depends on your plans and future plans. How long do you intend to remain in the house or the area? Realize house prices are going to be pretty flat for the next few years and may still go down slightly, so if you do need to refinance that can affect you. Rates are most likely to climb, already this week they have come off the bottom for the first time for several weeks, what they will do in the next 5 years is most likely to rise. If you do transfer, how easy will it be to sell this house before you rate re-sets. Can you afford to carry the house when the rate re-sets?
All this being said, talk with a mortgage broker, Eric May as noted by Rob Hughes is a good mortgage provider out of our office, there is also Jeremy Durkin of Prosperity Mortgage in the same office. I have posted a link to a list of local loan officers who all offer good rates and can assist you in making the decision. There are other options such as a 10 year arm, rates are a little higher but still less than a fixed and give you slightly longer before the rate will rise.