I use a CD shelf for my NES games. It works out near perfectly. Shelves that are too deep require you to put things in front of each other, but a tall CD shelf is just great for video games.
Each regular unit contains 19 NES games, and the bigger, horizontally stacked ones have 27 games. On the second shelf, you can see that almost any system's games, boxed or otherwise, fits very nicley inside. CD shelves really are the best for display in my opinion.
