A good holster and belt and either OWB-IWB will work just fine for most people. I carry both ways depending on the handgun, weather, and clothes. I have a Para LTC I carry IWB and it's just fine. I have an IWB rig for a Gov frame 1911 but usually will carry those in a OWB as most the time I have a full size 1911 I'm target shooting.
Here's a simple truth. 60% of the people that carry a handgun probably have a box or drawer of holsters. I sure do!
The first thing you really need to do is find a really good belt. It will not matter how good the holster is if your belt is some limp dish rag then any rig will not hang right. A belt made for wearing a holster makes all the difference in the world.
Some people like the kydex stuff, some it has to be leather (like me!) but neither will work right without the right belt. I have one I bought at Sportsman's Guide
several years ago that has been great. But there are better ones out there and most the time when it comes to leather you get what you pay for.
If you do go IWB make sure to get one that actually will hold it's shape when the pistol is not in it. It makes it MUCH easier to re-holster.