Most people stay with the stock needles, unless there's a specific color scheme they are changing to. I changed to blue needles, Capote changed to green ones. Off the top of my head, I don't remember anyone else switching to different color needles. The big thing to worry about, is mixing colors. This doesn't work well with LED light.
For example, in Aarkon's pic, those are the stock orange needles, but with a blue LED light behind them, they look red. Only way for an LEDs true color to show in the needles, is to have needles of the same color, or white/clear. Any other combination, and you'll get a mixed color.