If you need a good night's sleep near DIA, without breaking the bank, we highly recommend the Spark hotel. Our room faced the street and yet we didn't hear any air or road traffic. Not a single sound.
Great water pressure, plenty of hot water, and eco-friendly "supplies". Bed was also comfy and the linens were comfy.
We thought parking should be included for people staying there, and their breakfast really needs some protein options, but other than that it was a great stay!