This has been talked about many times here, if you search for LCD in this forum you'll find tons of info.
However, in short:
Cheaper displays, especially those integrated on lower end laptops have NO scaling ability. This means if you run 640x480 on a 1024x768 screen, you will have a huge black border on the screen and tiny actual image.
Next if you have a screen that scales, and you happen to have a 1280x1024 screen the 640x480 image will qudruple every pixel making for a VERY blocky image.
On a non 2x scale, if the panel scales, you will end up with a very soft image, sorta like turning hardware stretching on in Mame on a CRT.
So, you will have one of 3 problems typically, unless you let mame scale to the appropriate size (and also tell mame the actual pixel size of the monitor on every game) which then means you also will end up with softer pixels and require more hardware power on your video card and more CPU power.
To top it all off, you won't want to use an LCD, even the absolute BEST quality ones, in a cocktail table. Why? Because even the best ones only have a +/- 80 degree or so viewing angle and when you're sitting down looking at the panel you will likely see negative or washed out images. Upright it wouldn't matter as much, but on cheaper panels two player games may be bad because neither player would be standing directly in the center of the panel, both off to the side and again not see as bright an image or strange colors/etc..
A computer CRT is best since it can scale to so many resolutions and require less CPU power to rescale to fit the screen (as it can find more matching resolutions the monitor supports) . An arcade monitor is even better if you only play the classics as it looks the most authentic, and with AdvanceMame requires the LEAST amount of CPU/Video Card processing power since it outputs everything 1:1 with no extra processing, but of course limited to the resolutions the arcade monitor supports.
Hope that helps.