As if you needed to ask. Meddling middle managers and executives who wouldn't be playing the game anyway.

Seriously? Normal of course. You should have asked what if only "Normal" or "Hard" difficulties available? (Catacomb 3-D). In that case I might consider playing on "Normal" but I would probably go for "Hard" anyway. ;)
It's the same for me, almost always games have "C" for Crouch and I have to rebind that to "Ctrl" since Thief games (or was it Quake 2) ;)

C for Crouch is for devil worshipers and lawyers.

LOL! I thought that's applied only for invert Y-axis for mouse look ;)

I forgot that one too, even though technically it is under the "graphics options".

This is just important to me as I am a laptop gamer. I don't have any fancy G-Sync or Freesync or whatever they are called.

If I set vsync off, my GPU (and sometimes CPU) will keep running at 100% for little or no extra gain to me. This happened to me when I tried some Quake graphics update mod, my gaming laptop fans started screaming at full capacity which I took to mean my GPU/CPU were running hot at 100%, which they were.

I was a bit surprised as the Quake mod was not really taxing or anything. I switched on FPS counter, and yep, since there was no vsync enabled, the game was calculating as many frames as it possibly could, even if in reality it could display only max 60 frames per second (because that is what my refresh rate was). It was showing that it was calculating thousands of frames per second, for no good reason.

I switched vsync on, then then the laptop became quiet and cool again, and I got a constant 60 fps which is fine to me.

Some say vsync introduces some lag to controls, but I am unsure if that is some kind of theoretical or real lag you can really feel. At least I haven't felt any "damn this is laggy!"-feeling even with high-speed action games with vsync on.

Occurred to me: If there's an option to disable mouse look, I will likely do so.

About graphics options that I definitely switch off, I don't recall which game it was which I tried recently, it had by default that "depth of view" or "depth of field" or whatever enabled, which basically blurs or "unfocuses" far-away objects and scenery if you are supposedly looking at something near you, and vice versa.

I just found that very distracting and unrealistic because where my cursor is pointing is not necessarily where my eyes are looking at the monitor. In fact, I felt that gimmicky gimmick just made the graphics look worse, ie. blurred.

Playing with mouse look since Terminator: Future Shock (1995), and that exact game have issues with inverted Y-axis on vehicles (it was always Y-inverted despite the mouse look settings). Duke Nukem 3D and other Build Engine games were okay, but since Quake mouse look become a must for me. I don't understand how it's even possible to play without mouse look nowadays, especially FPS.
The only instance where I disabled it was GZDoom source port engine for Doom, Heretic and others, only because vanilla games don't have it and it ruins the immersion with sprite enemies anyway (oh, Hedon...), in Heretic you can and should look up / down by using keyboard keys only. Call me purist if you like, but it's something more ;)

First thing I do is to go to the graphics settings. Depth of Field and Motion Blur are the first things I turn off, then I go to check the rest of the graphics settings. Everything related to "render distance" needs to be set to maximum (I can't stand stuff popping up out of nowhere - this is an immersion killer!), screen resolution should fit the native resolution of my screen, VSync needs to be on, AF has to be 16x and AA (depending on how demanding the game is) 2x or 4x. I adjust the other settings while playing the game (if necessary - I rarely play the latest games, so my GPU is good for max settings most of the time).

Second thing I do is to go to the sound options. I like to set voices to maximum and sound effects and music to ~75%. Not hearing what anyone says during a firefight might be "realistic", but... I simply hate missing dialogue.

Third thing is to check the keybindings. Having a german system (QWERTZ), I have Y and X below WASD. Some games have Z and X set to zoom in or out or to go back and forward between items/spells/wepons/whatever. Doesn't make a lot of sense on a german keyboard, so I change this to Y and X. And I'll immediately rebind anything that's assigned to caps lock! I hate it when I leave the game, start to type anything and... my screen's YELLING AT ME! Oh, and I rebind whatever is assigned to | <- that little sucker sits next to the left shift key and needs the Alt Gr modifier (on the right of the space bar) to be entered. Not exatly comfortable during gameplay. I have no idea where it is on a QWERTY keyboard, but on a german layout it's the most stupid keybinding I've ever seen ;P

Changing the keybindings is the most important thing. Otherwise something like this will happen.

Subtitles : on
Motion blur : off
Depth of field : off

Resoulition to 1920x1080 if needed
To Borderless window
Subtitle ON

And probably thats all.
and filmgrain :P

I usually start the game on maximum difficulty. Only if it's clearly too hard for me I turn it down.

Also, I always check that subtitles are on and what are controls (in case there will not be tutorial for that).

I turn graphics settings to max, and adjust things after playing a bit if it's lagging or I don't like some effects.
I turn on subtitles if they're not on. If possible, I change spoken language to more immersive one (e.g. playing Metro in Russian, Witcher in Polish) or if the location is more abstract I sometimes choose the one with better voice-acting (recently played The Void in Russian).

Radeon_Software_Overlay [off]

1440:900@16:10 / 1920:1200@16:10 [on] ## (If it's available, depends on the game, if not just 720p/1080p. Too high and it becomes a strain on the eyes, especially with lots of text)
English_Subtitles [on]

WASD [on]
Invert_controls/mouse [off] ## (Unless it's a Descent/Overload 6DF kind of game)
On my extremely cheap Biltema mouse I have two thumb buttons I usually set to inventory and map/flashlight.

Graphics [very high/ultra]
Fullscreen [on]
Shadows [medium/high] ## (Depends on the game and the age of the computer/GPU. Shadow is the first to go, then water)
Vsync [off/on] ## (Mostly off.)
Motion_Blur [off]
Depth_of_field [off]
Chromatic_something [off]
Film_Grain [off]
HeadBob [off]
Most_other_annoying_no-good_filters [off]

Music lower than voice.

Game_difficulty [normal] ## (Higher difficulty usually means more annoying SpongeBobs and not smarter enemies. Depends on the game and if I've played it before or not)