Obviously, a lot of it depends on your body, what's comfortable, etc.
For me, the Milt Sparks VM2 in horse hide is the right answer. Having been through lots (more than I care to admit) of high end holsters, the combination of the wide belt loops for stability, reinforced mouth, water resistance, and comfort, all add up to the best set up I've tried. I've got one for every gun I carry.
I've tried IWB kydex, and don't care for it. For OWB kydex, there seem to be a near-infinite number of options. The new Tenicor ARX is particularly nice.
That said, there are a lot of good holster makers out there, many of them listed here. Good luck with your search!