First off, take a look at the Monitor Comparisons section of this site to see what went into my decision-making.
I hadn't seen anyone use a TV as their monitor at the time that I did this project, so I debated between an arcade monitor and a PC monitor. I chose a PC monitor because of it's quality and flexibility: "Quality" in terms of DPI and screen resolution, and "flexilibity" in terms of being able to run any Windows application that I wanted to.
I didn't get anything fancy at all. It's a "Gem" monitor, and it was the cheapest 19" monitor that's sold by Global Computer Supplies. To be honest, this thing is probably not the monitor that I'd choose if I were looking for a 19" monitor for my main computer. However, for running the arcade classics, it's exactly what I need. It more than does the job, and the games look great on it.
I knew that I'd need a way to hide the "PC-beige" color of the monitor's bezel. I've seen people remove and spray paint their monitor bezel, but I didn't go this route because I get the odd feeling that doing so just MIGHT void my warranty on it if I ever need to return it. So, I used this heavy-duty black packing tape and just lined the bezel around the screen with it. Once it's in the cabinet, you can't even tell that the tape is there...all you see is the screen.
To mount the monitor in the cabinet I bought four super-heavy-duty triangle-shaped shelf brackets from Home Depot. They're rated at a weight that's way above what I need them to be, but let's face it: that monitor is pretty heavy, and you know that it's going to be subjected to a decent amount of shaking and rocking as you're playing. I wanted to be absolutely sure that it wasn't going anywhere. To mount the brackets to the sides of the cabinet I used the same size carriage bolts that I did for the sides of the control panel - 5/8". I used carriage bolts mostly for their aesthetic quality: the round heads don't look out of place at all on the side of the cabient. Like the bolts that hold the control panel, I spray-painted the heads of these carriage bolts as well as the washers that go underneath them gloss black, and I also counter-sunk the bolts so that the bottoms of the heads rest flush against the washers.
Here's a little goof that you can correct if you think a little further ahead than I did. See how I have two boards underneath the monitor there instead of just one? That's because when I was measuring where to mount the monitor brackets to the sides of the cabinet, the monitor was still on its swivel base. It wasn't until I took the cabinet for a preliminary test-drive that I found out that having the swivel base on the monitor causes it to rock around like crazy. Duh. I had to remove the base, which then made the monitor too low, hence the second board. It's no big deal, but it's one of those things that made me slap my forehead at the time.
I bought a huge piece of black poster board from a local art store. It was in their "clearance" section for only $5 because it had a crease in it on one side, but since it was way bigger than I needed it to be I just chose that end as the end to cut off. Such a deal! It was kind of a drab flat black, so once again, I busted out the hi-gloss black spray paint and gave it a coat. Word to the wise: use light coats so as not to saturate the cardboard.
I mounted the poster board onto the cabinet using plain ol' phillips-head screws (again, with the heads spray painted black), butted the front of the monitor up to the back of the poster board, and then traced out the outline of the monitor case from inside the cabinet (which of course would be on the back side of the poster board). I then measured how far in the actual screen part of the monitor was from the border of the monitor itself, and then traced out a square and cut it out of the poster board using an exacto knife. Of course, I was very conservative in the measurements of the hole to cut, so as not to cut too much out. It took a couple of times of mounting the board, looking at it, and unmounting it and making additional cuts, but it sure beat having to start all over from square one had I made the cut too big.
Once that was in place, I cut out a piece of plexiglass the exact size of the poster board, and mounted that in front of it. So in order - from back to front - it goes: monitor, poster board with a hole cut out of it, and plexiglass.