Depending on your budget, I would go with a Kahr PM9, an airweight S&W Model 38, 638, 442, or 642, or a Kel-Tec P3AT.
I own a PM9, a 642, and the P3AT. I feel well-armed with the PM9 and a spare magazine or two stoked w/127-gr SXTs, even as my sole armament. It replaced my PPK and 642 for pocket carry, and I always carry it on the street. I felt O.K. when toting the 642 and a couple of Bianchi Speed-strips, but if in a protracted gunfight, I would be wishing for a bigger gun. (No such reservations when carrying my PM9.) My P3AT is my lounging around the house in my sweats gun.
The Rorbaugh is a nice pistola, but pricey and hard to find. If you have the money, go for it, but get one with sights - Novaks, if possible. It's hard to hit people past 7 yards without them, esp. if they are behind cover.
The best pocket holsters are from Milt Sparks, Alessi, and Kramer. I use a Kramer for the 642 and (after trying my buddy's) have a Sparks holster on order for the PM9 to replace/augment my current PCS holster. I use Kel-Tec's clip for my P3AT.
Whatver you do, get a pocket magazine pouch to carry a spare magazine (or two) in your support side pocket or devise some stealthy way to carry a spare magazine on your belt. Always carry at least one spare magazine, a knife, and a flashlight.
Regards,
Andy