Trust me when I tell you that these cases aren't going to fall over--I have them angled in a way where that isn't going to happen. 
My only concern is weight so I've got something I'm going to do to solve that this week. I also was going for a minimalist look for not much money (materials were ~$35 total) and I do not like pressed wood/particle board. I also didn't want a flat base the entire depth of each shelf because that makes it a dust magnet and is a pain in the ass to deal with when you have over 500 games on one unit. I plan on building 1 more of these for my CD jewel case'd games and longboxes. Also considering we're going to move in about ~5 years to Idaho or Montana anyway it made no sense for me to spend any more money thus I designed these to be throw-away after ~5 years.
Also keep in mind I don't have building skills so being as simplistic as possible was also a goal. 
I didn't use pressed wood or particle board. Common board is a type of wood. It's a cheap and mildly soft wood. Works well. I have pics in the game room pics thread.
Total cost for a 3' wide, 6' tall, 6" deep (with a 10" base board) costs about $25-30. This ignores the cost of screws, because a box of screws will make like 8 shelving units.
As for dust. I don't have any problems with dust. 6" depth is the width of a DVD case, so the entire shelf is covered, no chance for dust except for on the cases themselves... which you will also have. I have boxes stacked on the top, so again, no dust, except for on the boxes, which would happen regardless. The 10" base board will gather dust, but again, it's a 4" surface so a quick wipe with a clorox wipe or a duster will take care of that, no problem.
