Shadows is the first one to get axed lower. Usually it helps, too. I try to keep resolution as 1600x900, but sometimes have to lower it to 720p...

I always take off motion blur and depth of field, I really hate those two settings.

I recall there was some other site with a similar test, where there was some ball going across the screen quite fast while a scene was scrolling at the back. In it the difference between 30 and 60 fps was much more visible, even so much that 30 fps did indeed look quite jerky in comparison.

If I could just find the link, I think I originally got the link from GOG anyway.

I usually don't need to.

I switch off Depth of Field and Motion Blur regardless of frame rate. I simply don't see a reason to voluntarily degrade the quality of the image. If I wanted a blurry image, I would have kept my old CRT monitor.

I used to switch Anti-Aliasing off on my old monitor, but on the new one (28'' LCD screen with 1920x1200 pixels, i.e. relatively large pixel size) I find that I need it.

Currently, AA and AF are probably the things that I'd switch off last, but I never seem to have to.

+30.

60 is max because I use V-sync and it is a must in my screen otherwise tears a lot. In some games it doesn't work even if it is forced on at driver level. Well, those games are kind of rare luckily. Perhaps some indie games and dosbox is sometimes being an asshole.

If it is a first person shooter, then it must be higher framerate I guess.

I'll have to use pretty large resolution because of my monitor. 1920x1080 is my native but in newer games it is starting to cough. =/

I'll usually cut also from shadow quality and some lame ass SSAO effects.
If I had 2 gig video card maybe that resolution wasn't a problem. Big screen, plenty of trouble and needs. =)

http://frames-per-second.appspot.com/ ?

I have stuff like motion blur, depth of field (unless other effects are tied to it *cough* Warframe, Blacklight: Retibution *cough*), etc. disabled most of the time anyway.
I tend to lower AA (post process/FXAA/MLAA I try to eliminate regardless of performance), then shadow quality (but not remove them completely) and AO first. If performance is still an issue then I'll lower shader/effects quality. I prefer not to lower resolution and texture quality, unless they're causing issues.

Never disable AF or lower it below 8x, performance gain is negligible and the visual impact is huge (and more obvious the higher the resolution you use, I think)

I've found that 30 FPS with a keyboard and mouse is not very great, especially if the game syncs the mouse controls with the framerate (no game should ever do that, and yet every game does that), but with a controller, 30 FPS is very much tolerable and feels fine.

Personally, I think 60 FPS is ideal, but I'll still settle for 30 if I have to. What I hate more actually is when the framerate fluctuates between 30 and 60 and anywhere inbetween. I value smoothness more than framerate, and everything over screen tearing. There are people who can't live without antialiasing and can deal with screen tearing, but I'm the exact opposite.

Ah, that site! I had forgotten about it, it's better than the first and more close to what games are like. It's easy (at least for me) to spot the difference between 60FPS and 48FPS.

Before I became obnoxious about framerates I barely noticed lag so I guess ignorance is bliss in one way but on the other hand it's one of those moments you can't prove scientifically but it still feels like I enjoy it more to look at a screen at 60FPS if I care rather than look at 30FPS when I don't care. It's like emotional people; they have it extra rough when times are hard but when they're happy, they're super happy.

As for Anisotropic Filtering, I also recommend at least 8xAF as the performance difference between that and off is low and the difference in texture crispness is quite high. If AF makes a performance difference you've substantial evidence that your computer is too weak compared to the game you're playing.