Mucx wrote:
If it were me building it (and I've often thought about doing a mini arcade version) I would use MDF as the wood as it is lightweight yet durable...plus easily cut with a simple jigsaw cutter.
MDF is not light, it is heavier than plywood. That said, it is much easier to work with (though much more toxic because of the glue). I went with good quality plywood on mine for less weight and resistance to expansion from moisture. Plywood will last you a lot longer than MDF, though MDF is cheaper.
Making your own cabinet isn't easy and most newbies I tell just to get an old JAMMA cab from an auction for cheap (don't get any classics, that's just mean to those of us who restore cabs). However it is really fun to make your own. I probably put over 400 hours into building my cab and with all the parts and whatnot it came to about $2,200. I went all out though, obviously you can go cheaper. Much of what Pixelcade says is spot on.
If you build your own, start by getting dimensions of an actual cabinet shape you like. You can modify from there. Don't try to do it all on your own as most likely you will end up making some costly mistakes. Making a MAME cab is fun and while super time consuming is a blast once it's done. I absolutely love mine, and I built it about 7 years ago. Still gets a lot of play in the house. Here's some pics if you're curious:
http://www.flickr.com/photos/vitaflo/sets/72157594349201164/