Black only absorbs infra-red heat rays so unless you're going to be showing off the heatsink to the sun, the colour doesn't matter.
I'd definitely fit a case fan though. A nice 12cm fan at the back and possibly one at the front should do. No need to go overboard though.
Regarding CPU/PSU, I didn't edit it to be patronising, I edited it because I read my post and thought "Oops, bit of a fuck-up there" and hence I corrected it.