Try a Glock 19C. It will give you concealability, reliability, and great accuracy, as well as all the other criteria you want to meet. The ports in the barrel make muzzle flip nonexistant and follow-up shots are very quick. The 15-round mag makes it a competitive choice against a full-sized gun of another manufacturer. If that's not enough, you can also use the magazines from the Glock 17, which hold 17 rounds, or the G18 mags, which hold 33 rounds. Ability to accept a flashlight is also a plus.