I find white balance to be the big problem at roller derby, so normally set a custom WB shoot in raw and sort it all out later.
I've shot with and without flash, and how use a wireless flash set-up, if using flash you really don't need that fast a shutter speed in derby and can get away with 1/200 sec normally.
I'm still learning how to shoot derby to get the shoots I really want, but the local league have not had many bouts lately as they are moving from the local sports hall to their own permanent venue, which they have nicely lit with daylight bulbs for us photographers, or so I'm told

I also have the first outdoor bout in a few weeks time.
Without Flash
Two wireless triggered flashes
As for editing I use Apple Aperture or Photoshop Elements 8