Flagstaff Arizona claims to be the least light polluted city, and I believe it. I took this only 7 miles south of the city, right in the shoulder of I-17! The stars were so bright it was humbling. During the 30-second exposure, a couple passing cars lit up the evergreen trees very nicely for me.
Canon 5D Mark II, 16-35mm @21mm, f2.8, ISO 3200 and lots of post processing in PS CS5 to clean up noise.