For everyday wear and to help the breasts regain their shape I always recommend soft cups rather than anything padded or moulded. (Soft means underwired and non-padded / thinly padded). The soft cups will help your breasts to get back into their best shape, in other words -- to recover from being squeezed and distorted by previously worn wrong sizes. The breasts firm up, armpit rolls (in reality: escaped breast tissue) return to the breasts. Soft cups allow for that, since they don´t dictate the shape to the breast, rather they take on the shape of the breast. Moulded cups have a fixed shape, and the breasts have to kind of pour themselves into the mold (that doesn´t help with breast firmness !). The same goes for push-up and cleavage enhancing bras.
After a few months of wearing correctly fitted soft cups, your armpit rolls should go away (or rather return... to the breasts) and you should notice more firmness. Now you can start with padded and moulded cups, for occasional wear under clothes that require it. But for everyday wear soft cups are recommended. And chances are that you´ll love it that way. And, the breasts don´t always look bigger in a padded bra, and here´s the proof.
This is not about replacing your current padded/pushup for a soft bra in the same size; you need to get a soft bra that is correctly fitted. It is easier to establish your correct size in a soft bra. If the bra is correctly fitted, your breasts have got the chance to recover the tissue that has migrated out (to the armpit and back) due to the pushup bra. Actually, pushup bras should be renamed pushout bras, since they manage to push some of the breast tissue out to the armpits. Like this.
Soft cups can be made of a thicker material with a slight padding, but the cups stay soft and are different from the stiff padded or moulded bras, where the cups stay stiff even when you put the bra on the floor.
Nipple show is often a concern with soft bras. However, getting fitted with the correct size often solves the problem, as this reader pointed out.