Blue Cat's Digital Peak Meter Pro (Direct X) for Windows

The metering capabilities of the new DPMP let you control and monitor your audio signal exactly the way you want: almost every aspect of the meters can be customized. It now proposes five different scales, including Bob Katz's very popular K-System scales (K-12, K-14 and K-16). The graphs let you see the evolution of the audio envelopes over time, and the mid-side switch lets you verify mono compatibility problems and check the "stereoness" of your audio sources very easily.