i've yet to ever meet anyone whose adjustable rate mortgage went down. for the most part it seems like even if the rates have gone down the mortage company will jack it up at least a little bit because they figure if you want a lower rate you will re-fi.
allot of the foreclosures around our area were because of people that got 'great' deals on adjustable rate mortgages, but when it came time that the initial period was over they found that either their income had'nt gone up quite as much as they anticipated, their expenses went up allot more-or in most of the cases, the market tanked so much their houses did'nt qualify for a re-fi (owed way more on it than the house was now valued at). you have to look at the fine print on an adjustable and see how often it can be adjusted once that fixed period is over-we had neighbors for whom a quarter percent was'nt a big issue, but when it kept going up a quarter every six months-that was a big issue. buying with one because you figure you'll move before it jacks up can be problematic too-buyers of our home found that by paying their's off even a few months early they had to pay a penalty of 6 months of interest
even with a fixed rate, i don't think someone should buy more than they are comfortable with-unless they have the liquid assetts to make payments in time of need. i thought i was covered in 'time of need' cuz i had decent savings and short and long term disability insurance if anything happened to me or dh. it did'nt make up the shortfall when the kids had illnesses that kept me off (rotten monkeys-never got sick at the same time, always timed it so one had me off and just as he/she was headed back to school the other one came down with it

), when i did end up off sick myself i found that between the waiting period and the processing time for those policies you can be looking at as much as 6 months without pay (nice once you get it retro-but that does'nt wiave those late mortgage fees or the impact they have on your credit rating).
i look at the people who bought our home (619,000)-they could afford it on paper, but if one of them lost their job, their health insurance premiums went up significantly, commute costs increased significantly (and gas and tolls have almost doubled since they bought), one had to or wanted to be a sahp (and that seemed to be an issue with allot of the parents in our area-the kids got older, their were more negative issues in the public schools that were influencing them...had a good number of moms decide to become sah's as the kids aged)-it was'nt going to be a choice on keeping the house or not-it was going to be a matter of hoping they could sell it and clear enough to pay the realtor and then come up with deposits for subsequent housing.