My OB specifically advised not using anything that would restrict airflow to the skin. The hospital gave me strips of fabric treated to wick away moisture and limit infection (brand name InterDry) to put over the incision area until there was no more weeping/fluid coming from the wound. For what it's worth, the outer skin was closed with steri-strips (instead of stitches, glue, or staples) which were removed at my checkup 10 days after surgery. The incision is inches below even my lowest underwear waistband, though I preferred wearing ones that stayed a little closer to my belly button while my insides were still very tender, but I never needed to buy anything different. My incision has healed very nicely - no raised skin, very slim scar - it's just darker right now (12 weeks after surgery) and will lighten gradually over time. I thought it would be much worse than it is.

One thing I did find really useful during recovery was the simple support band I got during pregnancy - I used it more after birth than during pregnancy. This is the one I had: http://www.amazon.com/gp/product/B009LA4VOG I could easily position it where it was most helpful and quickly get it on/off for bathroom trips - before I could comfortably get into non-maternity pants, I would wear it over the panel and then fold the excess panel fabric down over it. It helped keep the maternity pants from falling down as well as provided extra support.