The Kill-A-Watt EZ is the big brother to the Kill-A-Watt. It has all the features of the Kill-A-Watt but also includes the ability for users to energy their kWh rate so they can see what appliances cost them to operate (without having to do the math themselves). Power cost information is retained by a battery backup.
The PowerCost Monitor (PCM) is a whole home energy monitor that "reads" your electrical meter on the outside of your home.
The Black & Decker EM100B Energy Saver Series Power Monitor is the PowerCost Monitor manufactured by Blue Line just rebranded by Black and Decker. It looks like Black & Decker is no longer branding this product. The only tool under the energy category of the home and office section of their website is the thermal leak detector.