8600k or 8700k

Im going to be building a pc just for gaming with a 1080ti what would be the best cpu 8600k or 8700k or would ryzen be a better choice?

The 8700k offers the better gaming performance of the lot overall.

Rather than advise on each component in isolation e.g. GPU, CPU, etc, it might make more sense to discuss the spec overall in the context of your budget.

What's your budget? Is this the budget just for the PC tower, or do you need monitor, keyboard, anything else included?

Will you be streaming your gameplay or doing anything other than straight gaming?

What monitor are you pairing the system with?

My overall budget will be about £2000 just for the tower and I’ll be using it just for gaming I will be using the ASUS VG248QE but I’m going to upgrade to the ASUS ROG SWIFT PG278QR in a few months.

In all honesty I'd suggest holding off until you're ready to buy the monitor and the tower together.

There's not much point buying a GTX 1080 ti and i7 8700k combo if both might already have been superseded by the time you get around to buying a monitor worthy of the system.

New motherboards (chipsets) and CPUs are expected from Intel in the coming months, and Nvidia will release Turing or whatever at some point in the not-too-distant future.

In that case do you think ryzen 2700x would be the better choice with a x470 motherboard

No - the 8700k already offers a bit better gaming performance than any other CPU.

My point is that if you buy something now - Intel, AMD, Nvidia, anything - it may very well be obsolete by the time you actually buy a monitor that lets you appreciate its performance.

So it makes more sense not to buy the system at all until you can afford to get the monitor too.