Jesse - Great question and there is no right or wrong answer. I own several investment properties in Fort Collins as well so I understand your concerns. Before making any decision, try to estimate how much your ARM will adjust as a worst case scenario. Would you still be able to remain solvent on your investment or will you be losing money? Do you enjoy the tax advantages that go along with owning an investment property? I know I enjoy reducing my taxable income each year. Have you kept up with maintenance on the property? What about upgrades? If you put your home on the market then you will want to give buyers a reason to buy your home and not one of the many other homes you will be competing against. Imagine yourself as a buyer looking at your home. What would you want and expect? Today's buyers expect a lot for their money so you need to distinguish your home from the competition. This could be fresh paint, new carpet or hardwood, or superior curb appeal. Also, you need to determine your target market but your realtor should do this. Is it an investor, first time home buyer, relocation, etc. Knowing your target audience is the only way to understand how to properly market a home. There are 7 keys to home selling success, in my opinion, and you can view them at my blog: http://www.FrontRangeRealEstateBlog.com.
Do your homework before making any decision on the future of your investment!