Building a gaming PC for 4K

Okay, I didn't see a "computer forum", and I think this isn't appropriate for On-Topic Discussions, but if I'm wrong, please let me know. I figured this was the most appropriate place for such a discussion.

Anyway, I just upgraded to Windows 10. Loving it so far. Since Windows 10 plays nicely with ultra-high resolutions, I'm thinking of getting such a monitor. Not 2560x1440, but something beyond that, either 3200x1800 or 3840x2160.

I'm aware of the fact that you'd need to spend a ton of money on a graphics card for high-end gaming in 4K. I might just play those games at a lower resolution, like HD. But I think 4K would be awesome for stuff like Rayman Legends and Ori and the Blind Forest. I am not a realism chaser, and few games with realistic graphics (aside from, most recently, Skyrim) have gotten my attention.

What parts would you recommend? What things are compatible with each other that would be great for such a computer?

I realize I'll need to reinstall Windows, which doesn't make me happy, but I'd be okay with doing it. Might there be a way around it? I guess not if I'm installing a new motherboard.

OTC does have a thread for you.

Thanks. Much appreciated.