We stopped using coax many years ago as well in favour of Cat5e. The cable itself is cheaper, even if you don't include the cost of separate power wire necessary with analog. It's also more flexible and easier to work with, and typically smaller diameter so you can fit more runs in a give space.
When we were still doing a mix of analog and IP on large sites, we also made use of these - they're a combined unit, rackmount multi-channel balun and 12VDC power source. The RJ45 jacks made it a snap to simply terminate all our runs into a patch panel, then use a regular patch cord to connect to the VPS for analog, or a switch for IP. Upgrading later is as simple as unplugging the patch from the VPS, swapping the camera, then patching into the switch.
Each group of four inputs also includes an RJ45 output carrying all four video signals over a single Cat5e - on a couple of sites we used this feature along with a rackmount multi-channel balun in the rolling rack, to allow us to terminate runs in a wall rack, then cross-connect to the rolling rack with minimal cables; we then had the rackmount baluns on the rear rails directly behind the DVRs, making for easy, direct connections to the DVR input tails.
But enough of that sales pitch (disclaimer: I do not work for Eastern CCTV and never have, but they were our supplier for the VPS units and always gave great pricing and service). We're not installing analog any more, and most sites, when an analog camera fails it gets replaced with IP. As Mark says, having used Cat5e makes the upgrading painless.
Using UTP instead of coax has also allowed me to do some sketchy stuff out of pure necessity... for example, one site was near completion and they wanted us to add a camera to an outdoor location, but all exit points were already sealed... I took the Cat5e going to the nearest outdoor camera and split the pairs off, orange for one camera's video and green for its power; blue for the other camera's video and brown for its power. Fortunately the cameras require very low current and have a wide range of operating voltage, so even with the voltage drop over some 200' of 24ga., both cameras worked just fine. A couple years later one failed and they wanted to replace it with an IP camera... fortunately we were using a good PoE switch that supported mode B PoE (phantom power over the data pairs - most cheap PoE switches don't do this, sending power only over the other two unused pairs), and for the last two, almost three years, I've had one analog and one IP camera running over a single Cat5e. Best practices? Not even close. But it works and that's all that matters.