Your report is quite favorable. Are there any stations that you particularly want?
You'll want an antenna that includes coverage of VHF high real channels 7-13 and UHF channels 14-51. An antenna like the Antennacraft HBU22
http://www.antennacraft.net/Antennas/AntennasHBU.html mounted on your rooftop should work great. The RCA ANT751
http://www.amazon.com/RCA-ANT751-Dur.../dp/B0024R4B5C should be ok too, to get all the majors from Denver. You'll want to mount your antenna in the clear air above your rooftop, with no trees or neignboring buildings between the antenna and the stations you want to receive.