well, i wasn't necessarilyl building a cabinet...i planned on getting an existing cabinet for cheap and installing the components i already have. (26" tv, and either a PC or ps2) i figured i could put one together for very little money...otherwise i just can't do it right now. My wife approval rating is hovering around 0 right now...she really doesn't want me to get another cabinet...i'm trying to convince her that it would cost very little money, and since the i plan on using the TV that is already in that room on a little stand..that it won't take up much more space, and my son can still use it to watch TV on during the day. there is a local operator who has sold me empty cabinets in the past for around $20.. i already have a PC that is usable (athlon xp 2500+, 1gb ram, 80gb hd, geforce 4 mx440), as well as a spare playstation 2, 2 guncon 2 controllers, and even a 2 player x-arcade unit that i could use as well. all i would have into it is the basically the cost of the empty cabinet and a few odds and ends. i used that TV with the PS2 in a cabinet a few years ago, but got rid of the cabinet when we moved...yeah, the picture quality isn't great..but it is ok for shooting some bad guys.
if andy or someone else comes out with a good lightgun option for LCD monitors, then i'll eventually get that and use it with my regular mame cabinet, but for now i'd love to get some light gun action going.