If they display a single then it's likely the total (rise+fall) which is what you should be concerned about. If they display rise&fall seperately, just add 'em up. If 3D is important, try to stay <30ms which is still twice as slow as a typical CRT but minimal blur/ghosting.
Respons time is a measure of how quick the pixels go from black to white - and back again from white to black.
Response time is the total of the two, whereas rise time is black to white and fall time is white to black.
So when you have response time the preferred value should be below 30 ms - and if you have rise time and fall time, the two added up should be below 30 ms.
The only way I heat up my house is by overclocking my cpu :tongue:
even then it is often overstated since intermediate tones may take even longer to change states completely.
That said, don't get too hung up on spec's - most people seem to be happy with their screens. If you are a hard core gamer staywith CRTs for another year or two. LCds will only get better and cheaper ....$300-400 will get you a great CRT or a mediocre LCD.
In theory, there is no difference between theory and practice; In practice, there is.