Does Color Really Matter?

The short answer is yes.
My M Roadster came with an after market head unit that is a brushed aluminum color. It sort of matched the chrome rings on the gauges (not really).

Here's the one that came with the car.

Here is the one I swapped into the car.

Originally BMW equipped this car with a black head unit, pretty sure it was AM / FM / Cassette. I've always thought it was very plain and did nothing to help the center console look good. After living with the brushed aluminum look for a few months I like black.
Maybe BMW got it right after all.

A little about the swapped in unit. It came from my '97 328 convertible. I replaced the original BMW unit with this one a few years ago. It took a lot of searching to find one like this, I don't know if there are any made like it anymore. What makes this unit so special to me is that it has a USB port and a 1/8 inch AUX input on the front.

I wanted the ability to plug anything into the head unit and have it play out of the car speakers without having wires run into the rear of the unit.

The USB port will take any USB hard drive (external hard drive, thumb drive, memory card adapter etc) and it will also take an iPod connection. I have a memory card adapter that is very small - it sticks out less than 1/4 inch - and it holds 8 gig of music. I leave it in all the time. I never need a CD player, but if I do there is one behind the face.