White is generally good for high-contrast or high key shooting. If your style reflects this or you're interested in that kind of photography, it's a great place to start. Also makes it relatively easy to switch out in photoshop if you want to replace it with something else, and your PP skills are that good.
Black is also v. good, and is pretty standard in any kit, my only thing with black is it attracts dust easily and it shows up on cam if you don't keep it clean regularily. I see a lot of people using black blankets or cloth, which aren't too appeasing to look at as the folds and the creases are distracting (some are grayish, stands out as distracting in light) and they attract dust. Don't use a blanket as a background.
I use a lastolite collapsible muslin/background. They're pretty cool. You fold them sort of like reflectors, and they spring up fairly easily; light and transportable. Mine is white, as I can use gel lights to color it if necessary. I'm cheap like that, try googling Lastolite collapsible backgrounds