My favorite time to shoot is at twilight. Color in the sky makes all the difference. Also having a fast lens and not being afraid to push the ISO provides lots of creative options. This shot, for example, was recorded wide open with the ISO set to 1600. I haven't done any noise reduction at all.
If you also like this stuff, consider entering this month's Photo Assignment, "High ISO." Entries must be shot at ISO 800 or higher.
"American Flag in New York City" -- Recorded with a Canon T1i and a 50mm lens at f/1.8. Thanks to ISO 1600, I was able to expose at 1/30th to give me a good rendering of the flag. Photo by Derrick Story. Click on image for larger version.