See, that's what I'm primarily loading up. Early 80's stuff; a certain game involving a gorilla, one involving a spaceship and flying insects, one involving burgers, little yellow dude who runs from ghosts....you get the idea.

is it gonna look decent on a computer monitor? Any necessary tweaking?
Wow, those game descriptions sound WEIRD. hehe
So DK, Galaga, Burgertime, and Pac Man... all the oldies. All vertical too which brings up another thing (well for me anyway, stretching and/or wasting screen real estate).
With a PC monitor, very good video card, and some tweaking of the d3d effects you can get it looking close. For me, after 4 years or so of the PC monitor and going to funspot all the time I just really wanted the large dot pitch and grille mask of an arcade monitor. But I'm also extremely picky so I might not be the best guy to listen to. You might not notice or even care.

I bet for 90% of the DIY arcade cabinet population a regular PC CRT is fine. I went overboard on everything on my cabinet and the monitor was no exception.

I get all the juicy old school modes on my tri-sync 19".
Vectors look much nicer on a PC monitor for sure though.
Hope this doesn't muddy the waters too much for ya.
There are some older pictures of my decased monitor on my cabinet site (see my sig). If you are looking to see what's involved in decasing etc.
~telengard