Anyone who's read the expanded PDF of the DSLR Guide knows that I use Neat Video for noise reduction. While the results are top-notch, I do have some issues with the plugin: namely, that it doesn't take advantage of the host machine's graphics card, and as such the render times can be quite slow. A new entrant in the video noise-reduction market is Magic Bullet Denoiser, which ships as part of the excellent Magic Bullet Suite 10. I haven't had the chance to fire up the plug-in yet, but there are a few excellent reviews and tutorials already out there:
Patrick Inhofer has posted a great video review/tutorial of Denoiser at Tao of Color; you'll want to make sure HD is on and that you full-screen the video to be able to see the difference the plug-in can make:
Second, Scott Simmons at PVC has a review of the plugin; he reports a few errors with the plugin, and unfortunately I've found this to be the case with a number of Magic Bullet's tools (however, they are very aggressively priced, and I find myself forgiving of the occasional crash given the value). But Scott seems to like it overall, and he makes a number of helpful sample clips (though they're mostly of home-video baby footage) available.
Finally, there's also a tutorial on using Denoiser at CreativeCOW.
I'll be putting it to use in the weeks to come, and will try to compare it with Neat Video (in terms of results, speed, and stability) when I do so. For your own purposes, however, you can always give the free trial version a shot.