I agree with going someplace that at least has a nice selection to fondle, and even better shoot. Pick what calls to you, not what someone shouts out to you. I think what you shoot best with, with what you currently own, would be a good starting place. I'm a firm believer in carrying what you shoot best with, which is usually the medium-full size guns. Except for the smaller pocket type pistols, there really isnt a whole lot of difference in size between many, if not most models, and when carried in a good IWB holster, just about anything reasonable can easily be carried if you dress appropriately.
I know a lot of people seem to like the small, lightweight revolvers, and I suspect most that do carry them, carry them a lot and shoot them little, especially the Airweight and lighter guns. If you do go that route, be prepared to spend a good bit of time practicing with them, and with ammo at a power level you intend to carry in the gun. They do take dedicated practice to stay on top of them, and its usually not a lot of fun practice. I shoot mine a couple of times a month, and a box of 50 at an outing is about all I can take anymore, and my hand isnt happy with me for a day or so after either. I would highly suggest you do shoot one with realistic ammo before you buy.