It's one thing to hear that Lightroom 3's new processing engine does a superb job of controlling the digital noise that can mar low-light images. It's another to see the effects up close, so let's have a look.
In Lightroom's Detail panel, the left "Before" version shows big-time noise in the 1:1 window. In the right "After" version, the Luminance and Color sliders have been moved to 14 and 19 respectively. The Detail slider for each has been used to keep the photo from becoming a noiseless —but totally smudged—watercolor. Yet even with this relatively conservative correction, the color noise is completely gone, with just a hint of luminance noise remaining (the pixelated edges visible in the black area).
After slightly boosting the Luminance slider to about 20, see how smooth the black jacket and blue shirt behind it have become? Like I said, the effect's startlingly good—even on a snapshot like this. Just imagine what your results will be with a DSLR.