There are going to be the typical "Who cares! As long as it sounds good!" responses. But I wonder if these are also the type of people who wear pyjama pants in public because they're comfortable or drive a certain gas guzzling beater car because functionally it works fine, so...who cares!
For me it doesn't so much have to do with matching as it does uniform placement. Black is best, I'm not into red, white, green, purple or animal skin amps and cabs. Sorry, not my style.
So basic black it just fine. After all we're talking about electronics and speakers here, not Ikea furniture.