A PC monitor is the simplest and most direct route to setting up a display for your arcade machine. PC monitors provide ok quality, are relatively inexpensive and are very simple to set up. As opposed to a television or authentic arcade monitor all that is required to display games on a PC monitor is to attach the monitor to your PCs VGA connector.
One negative to consider if you are thinking of using a PC monitor in your arcade machine is that games may tend to look slightly "pixelated" (blocky looking) due to the high resolutions that modern PC monitors run at. Enabling scan-lines (black lines across the screen) can make the quality better but it still does not compare to the quality that can be achieved with a television or better yet, an arcade monitor.
It is important to note that original arcade machines were run at quite a few different resolutions and some of these resolutions will look better than others on a PC monitor. A simple PC monitor connection will never be able to give you a truly "authentic" arcade look due to these resolution issues but software tweaks and resolution adjustments can create an acceptable picture.
Fans of Vector arcade games should consider the following fact when considering PC monitors: The higher resolutions available on PC monitors create what many consider a better picture when emulating vector graphics (compared to TVs or standard arcade monitors). This is because the higher resolution (generally SXGA and higher, though XGA will do, even on a 27" CRT) makes for much smoother graphics (lines) and greater anti-aliasing. (The latter is in regard to an object or line in motion, and how continuous it appears. On raster-type monitors, due to how they draw, there is usually a perceptible watery effect.) With the high prices of Vector monitors and the Zektor Vector Generator ZVG Homepage, a PC monitor could create an inexpensive alternative to a vector machine for those willing to sacrifice a bit of authenticity for lower cost.
When you want to use a LCD monitor for your arcade, you need to think of even more things. Where a CRT monitor is multisync, it can adjust to many resolutions quite easily, with optimum scaling quality. An LCD on the other hand has a fixed resolution. Other resolutions than the native one are scaled up with anti-aliasing. Check if you like the results first. You are also limited to refresh rates. A CRT can show any refresh rate from 50-100 Hz exactly as intended. LCD screens mostly have a fixed refresh of 60Hz. A 50Hz game can look jerky when displayed on a 60 Hz LCD.
Second problem with an LCD can be the aspect ratio. Most arcades used to have 4:3 screens, wide or portrait. The biggest LCD monitor available in 4:3 aspect ratio is a 21.3 inch screen. Good thing is that these 21.3 inch screen are all high quality S-IPS or S-PVA screens with pivot options. If you want bigger, it means you have to accept the 16:10 aspect ratio. Do not try to find a big 4:3 LCD TV. They do not exist. 21 inch is the bigest 4:3 LCD TV available. These 21 inches are all low resolution 640x480 or 800x600 screens based on TN-panels with bad viewing angles and bad blacks.
Third problem is signal processing. LCD monitors sometimes make calculations between 2 or 3 frames to eliminate ghosting or to simulate more colours (TN panels are 18-bit displays by nature). This creates a so called input-lag. Check reviews to get an insight in real world numbers, but as a guide you can use this list:
TN-panels - cheapest - no ghosting - bad vertical viewing angles and mediocre horizontal viewing angles (light tint clipping or reversing, solarising effect, gamma unstable) - watch out for input lag on big TN panels (>23 inch) as PWM high-colour simulation creates lag. - watch out for TV-models, as tuners can add serious lag - all in standard sRGB gamut - static contrast 1:800-1:1000
IPS-panels - double price - great viewing angles (best) - little white-glow on extreme angles (black becomes lighter), but gamma curve stays nice - in big sizes FASTER than TN (the fastest and best large game screen was an IPS display!) - available in wide-gamut (more saturated colours) - suitable for vertical mount - static contrast 1:800-1:1000 - budget IPS is available now, for example the DELL 2209W
PVA-panels - double price - great viewing angles (slightly less stable than IPS) - little yellow-shift on white at extreme angles, gamma stays nice - worst input lag (2-3 frames) for monitors, still better than some TN-panel TV's - deepest blacks. 1:1200-1:2400 static contrast (Samsung F2380M is current contrast king) - suitable for vertical mount - available in wide-gamut (more saturated colours) - budget S-PVA is available now, for example the Samsung F2380M.