For the moment my answer is a SIG P239 in .40, carried in a Kramer Confidant holster shirt. I also carry one spare mag in an Uncle Mike's knife pouch in a front trouser/jeans/shorts pocket.
I've worn this combo for up to sixteen hours straight with very little discomfort and strong concealment. It's definitely not the fastest rig out there, but I can carry just about anywhere without having to be concerned with a jacket/vest/untucked shirt, etc., as a covering garment. I wear the Confidant over a t-shirt and under a good button-down shirt, short or longsleeves, and I'm good-to-go.