Like I have said before - Support 'em if you got 'em. Let me tell you I think the Enell Sports Bra is going to keep your girls in line. The bras were designed specifically for large breasted women to enable them to workout and play sports comfortably.
Made of double layered fabric, the bras create less friction and are ideal for long distance running. They are constructed from Naturexx fabric that not only helps dissipate body heat, but wicks away moisture as well. Their site has a page full of testimonials and Oprah's O magazine loves them.
They come in a variety of colors, and the pink one pictured is the Hope Bra since Enell donates $6 to the fight against breast cancer for every pink bra sold. You can order one online from Angel Bras for $62. I guess good support doesn't come cheap.