Conduit is the best way! If you need pull stations then put them in. There is no other really good solution at the moment and 8K/48gbs is coming!

The "virtually lossless" compression for Cat6 is noticeable. I don't know of a coax solution for 18gbs yet, but theoretically possible. Cat6 is going to have problems at 18gbs without using compression. Fiber can do it now and definitely has the bandwidth needed for 18gbs and 48gbs in the future. The only downside is the extenders are expensive. If for whatever reason you can't use conduit I would definitely pull fiber.

And lastly, conduit!