big fan of my hk p30L in 9mm
get something you can control raipidly vs something with 1 big boom that takes you seconds to get back on target
Second for the H&K P30L. This is a great gun. For conceal carry, get the P30, which I carry for around town. The grip is very customizable and the ergonomics are second to none. My wife competes in USPSA with her P30LS (S = safety) and loves it. She has shot about 6,000 - 8,000 rounds through it.
For the OP, to be clear, the greatest accuracy tool you can buy is a reloading machine. Practice is WAY more important than anything else. When you conceal carry, think about missing and where those bullets can go. Shot placement over caliber every time. When you miss, the caliber is useless. 9mm is cheap, easy to shoot, easy to practice with and with the improvement in bullet designs, wound cavities are much greater.
Stay away from revolvers. "Stopping Power" is a myth.