Originally Posted by testpie

Why? I'd be with you if we didn't have any power specifications for the products at hand, but from what Myst has said, the monitor is auto-switching, and therefore technically able to work on the UK power grid with little more need than a US-UK plug adapter, or a different kettle lead & the PC's power supply will be the same one they sell across the world, the main difference being how they flip the voltage switch in the factory before they send it to you/fit it in your PC.

Now, if we were talking about bespoke appliances only distributed in America (i.e. a certain model and variant of said appliance that is only distributed in the USA), then by all means get a step-down transformer - it's going to be your only choice; but if the equipment is designed to work with UK and US power grids, why not use that functionality?