I don't often use the PPK as a CCW, but when I do carry my Kahr MK40, I use the Bianchi #100 Professional inside waistband. My PPK snuggles up even better to that good Italian leather. When I take the PPK to the range and don't want to lug my range bag along, into the # 100 it goes. And it's comfortable. - onetros
Left to right, El Paso Saddlery shoulder rig, inside the waistband and outside the waistband holsters. If they're good enough for Doc Holiday, Wyatt Earp and George S. Patton, they're good enough for me. Seriously, the IWB is excellent. It retains its shape for easy reholstering and is very comfortable. The OWB is terrific too, very comfortable. For hand made holsters that will last several lifetimes, I think they're prices are very reasonable. www.epsaddlery.com
I've also got a Galco fanny pack that is terrific and sometimes the Fobus paddle holster works well. I don't believe there is any "do all, be all" holster so I have different ones for different occasions. (I cut the Fobus down because it is also made to accomodate the longer PP slide. It stuck out under my jackets. When I cut it, I had to use new bolts/nuts to secure the bottom).
I use the Smartcarry most of the time. I just recently bought a kangaroo industries shoulder holster http://www.kangarooind.com. The kangaroo is essentially a belly band worn higher with a strap over the shoulder to hold up the gun. It is comfortable and hides my PPK very well.