Generally speaking there is no "best" in noise reduction software. All of the market leading software options in noise reduction deliver similar levels of performence; though sometimes with certain types of shot one will outperform the others. The problem is that there is no distinct pattern to this outperformance so for most people its not cost effective (in money and time) to use all of the software options for minor advantages.
Noise Ninja; Neat Image (the one I use); Topaz Denoise are a few of the leading market options