The 30fps thing only applies to what is necessary to produce the illusion of movement to the human eye. It is not yet confirmed what the limits of the human eye's perception truly is, so in any situation, the higher the fps the better.
Now the refresh rate thing is more accurate. If your monitor only refreshes the image every so often, it's essentially a cap because the image is only cycled every so often (60hz refresh is a visible cap at 60fps, and 120hz refresh is a cap at 120fps, since the monitor can't physically recycle the image any faster).
So, basically, even if you churn out 300fps and you only have a 60hz monitor... Well, those extra 240fps mean jack.
EDIT: Just read Gunthak's post, and he basically summed this up perfectly. Ignore me please, haha.
Anyway, specs for a wide-range of equipment -
Laptop 1 -
Intel Core Duo @ 2.16GHz
2GB DDR2 RAM (2 x 1GB)
ATI Radeon X1600 @ 256MB
Windows XP Home Premium SP3
1440 x 900 Res. @ ~90fps - Settings on Normal (w/ no AA)
Laptop 2 -
Intel Core 2 Duo @ 2.66GHz
2GB DDR2 RAM (2 x 1GB)
Nvidia GeForce 8800M GTX @ 512MB
Windows Vista 32-bit Home Premium SP2
1280 x 720 Res. @ ~120fps - Settings on Normal (w/ no AA)
Desktop 1 -
Intel Core i7 920 @ 2.67GHz
6GB DDR3 RAM (3 x 2GB)
ATI Radeon HD 4870 @ 4GB (2 x 2GB)
Windows Vista 64-bit Home Premium SP2
1600 x 1050 Res. @ ~200fps - Settings on Highest (w/ no AA)
Desktop 2 -
Intel Pentium 4 @ 3.0GHz
2GB DDR RAM (2 x 1GB)
ATI Radeon 9800 @ 128MB
Windows XP Home Premium SP3
800 x 600 Res. @ ~20fps - Settings on Lowest (w/ no AA)
Screenies from Desktop #1 (using "stat fps", so it prints in the right-hand corner) -
Number 1
Number 2
Something about the Anti-Aliasing kills my average fps by about 100 frames usually. I've only experienced this kind of dip in KF though, as when I play other games on Desktop #1, I can crank the AA to 4x without a hitch, and sometimes 8x for a loss of ~20 frames.
For example, in CounterStrike: Source my settings are completely maxxed on Desktop #1, including HDR lighting, full AA, etc. and I average ~250fps. However, my monitor is only 120hz, so, anything over 120fps doesn't really matter I suppose.