I had the Nikon D3100 with me at last Saturday's wedding.
It was a great chance to try it out in low light indoors, not to mention mixed, less than ideal lighting.
Shot some candid and detail photos during the reception using the Nikon 50mm f1.4G on the D3100.
Here's a few (click on the image to see larger)...
Nikon D3100 @ ISO 1800
Nikon D3100 @ ISO 6400
Nikon D3100 @ ISO 3200
You can see the full-size jpgs at my Nikon D3100 Flickr set.
Nikon D3100 Unboxed
Nikon D3100 vs Nikon D90
Nikon D3100 Gamechanger
Nikon D3100... the Perfect Prime Camera?