I've never dabbled in overclocking as it's out of my comfort zone with what I know about so what cooler would you recommend for running the CPU out of the box?
Storage wise I was looking to have Windows on its own M.2 so wouldn't need a high capacity drive. I do play a LOT of games so would need at least 2TB of additional storage. I like clean aesthetics so the least amount of cables in the case the better so I'm not looking to have anything other than M.2 drives.
The "D" in D15 stands for dual. As in "dual tower"......the 2 separate vertical columns of fins you see.
Look for a Noctua with a U rather than a D. Those are single towers. Cheaper, lighter, and plenty strong enough for anything other than a heavy overclock on the 12600K. Such as the U12S or U14S. There are several variants of each on Noctua site.
You need to confirm case and RAM clearance is not an issue. Tools to do that are on Noctua site. Look for "compatibility lists".
I would NOT put Windows ONLY on a drive. Maybe you didn't mean that. Normally you'd want Windows and installed applications on one drive. Probably your fastest drive.
Some people also put their data on that same drive. Some don't. Personal choice.
Windows alone, fully updated, takes under 30 GB.
You're the world's foremost authority on your storage requirements....how much you need and the growth rate of that total. Get a grip on those numbers.
Ideally....you may want ALL data on one (possibly huge) drive, but your budget may not permit that.
Avoid spinning drives if possible.