I know I've read that with high ISO and night shots it's supposed to be a good idea to turn on the in camera noise reduction (Canon XSi in my case). What about at ISO 100? I'm going to be testing out my tripod at night finally tonight and wasn't sure if I need the in camera noise reduction or not. I don't expect any of the exposure to take more than 10-15 seconds if that matters. It's going to be for a car show/street fair in a shopping area so there is some lighting. Here's a picture from the shopping place's website showing about what the night lighting looks like, though some is a bit darker.
And here's one of mine from last year showing maybe a bit better the lighting at least in the darker areas. This was handheld at ISO 800.............