Ok feel free to talk about outstanding / crazy / weird / amazing / anything game packaging.
I will start by saying that the Mother series of games has some of the best packaging in the history of console gaming. Very understated, simple graphic design with bold, unique colors. I love how the series has a common theme for the packaging between Mother 1 [Famicom], Mother 2 [Super Famicom], Mother 1+2 [GBA] & Mother 3 [GBA]. This is the game series that inspired me to create this thread, as the packaging made quite a bit more impact than any other series.
Also, I really like the Japanese GC game packaging. The small boxes and slip covers are a perfect setup for collectors.
I started a thread in the Import Games forum about the Nintendo Developed small-box games for the Famicom, and I really like these as well. The boxes are basically the size of the cartridge itself with no plastic tray on the inside. I am attempting to get a complete collection of these Nintendo "small-box" games.
As far as cartridges are concerned, my favorite is definitely the PC-Engine/Turbo Hu-Cards are amazing. It makes them really fun to collect for some reason. Second would have to be the standard size Famicom cartridges. These are a really nice size & come on a rainbow of colors that makes each game unique.
The PS3 game cases are the coolest of the current generation home consoles, but I assume these are just standard Blu-Ray cases. PSP games also have practical, uniquely shaped boxes.