For controls: HOTAS, a second flight stick and a wheel + pedals. I use HOTAS in supercruise, twin stick + pedals in normal flight (although can still use HOTAS when I want). Twin stick is way better for combat (2nd stick for lateral/vertical thrust), and generally more pleasant to fly agile ships, but the HOTAS still feels right for big hulking bricks like a T9/10.
Wheel + pedals for the SRV. Main flightstick to control the turret. Feels much better than the HOTAS, and driving around shooting stuff with one hand on the wheel and one on the stick is great fun.
^ all of the above is set up to go all at once, no profile switching or programming software needed. ED's controls menu might not be pretty but the functionality is excellent.
You don't need the latest & greatest stuff, no need for FF wheel. My wheel and HOTAS were 2nd-hand and the extra stick was only £11 delivered. No DIY needed, but I do want to build some chair mounts. Right now it's all on the desk - I bought a tenkeyless keyboard so it'd fit between the sticks.
I use VR and I think it's the best experience, but if that's not an option get the biggest screen you can and head tracking. Then a second screen or device for eddb/inara/netflix/etc. Doesn't have to be a new monitor, if you've already got a laptop or tablet you're all set. Surround speakers or good headphones - no need to break the bank, you really don't need to spend much to make PC games sound great.
Icing on the cake for VR users is virtual screens in (or outside) your cockpit. Can't tell you how good it is to have a massive cinema screen floating above my ship while I'm mining or travelling. And for VR and non VR users alike, audiobooks are good