I'm large also and found that Hanes sports bras fit really well. They come in a really generous D cup, have nice wide straps and a wide band around the bottom. I buy the ones for high impact, though they come in a low-impact version, also. They make one that hooks in the back as opposed to pulling over the head (which is a drag for large busts!). On days I do vigorous cardio, I find wearing one cup size smaller than usual really helps hold things in place. Target carries the Hanes in three different colors for $9.99 each.

Hope this helps.

Brenda