I bought some loose-fitting, pullover, cotton sport bras before surgery. 9 weeks later, they are my current favorite.
I woke up from surgery with a nylon surgical bra on, provided by the hospital. I didn't take it off til my first shower 5 days later. It stretched out pretty fast, but it was comfortable. Very wide straps and wide elastic band. My only complaint was that the wide chest band had gotten curled up and left a deep dark red mark on my left side.
Underwires are still uncomfortable, anything that rubs at the bottom of my sternum. They can irritate my drainage hole sites as well, even though they are healed up nicely.
The first few weeks I was home, I was most comfortable in a tight-fitting tank top, the kind without a built-in bra, and have some spandex in them. The gave me the support I needed without anything tight fitting. I found that if I spent too much time with no support, my incision site was sore and irritated.
I bought some sport bras after the surgery that had a lot more support than the plain cotton ones I bought before. They were very difficult to get on and off, and I still have to ask for help if I decide to wear them. However, because they are tighter fitting, they were the MOST comfortable to wear all day. It was like a gentle hug