SlamDancer,
Since the Bryston BDP's and BDA's are low-current devices, practically any computer type IEC cable should easily provide enough current capacity to deliver power. Beyond that, however, I feel that any digital component with high end aspirations would definitely benefit from a good-quality shielded cable with quality connectors. The market is full of high end cables sometimes costing more than the components themselves. And yes, I'll admit I have drank the high end cable Koolaid with my components. But I think excellent results can be had from solidly engineered cables from value companies such as DH Labs, where a 3' Encore power cable will cost you about $100, and give superior results over the stock supplied cords. That's just one of many, many options. You might want to consult The Cable Company for trials. I think you will be surprised at audible differences between cables.