Im a DD and I wear a high impact bra from acadamey. Its the only one I found good enough to strap my chickas down. I absolutley love sports bras. I wear them like everyday they are just so much more comfy. Riding withour one is a bad idea for us big boobied folk.
Personally I am a two bra chick. I finished breast feeding two years ago and they never deflated! If I was a dairy cow I would be a prize winner!! I wear a regular underwire bra and over that a lycra sports bra bought to be just slightly to small so everything is kept nice and firm. Works a treat.