No Particular Order...
1.) Japanese Nintendo Packaging: gameboy, famicom, super famicom, and more recently gamecube.....the Japanese Nintendo packaging almost always looks better in my opinion
2.) Japanese MegaCD/Saturn Packing: standard cd jewel cases....
3.) Super Famicom: is it me or is the original super famicom the best looking of all versions?
4.) Famicom/Super Famicom Carts: any day over the US iterations
5.) Panasonic Qube: definitely the ultimate version of the gamecube
6.) Japanese Coverart: sometimes its just the prettier boxes, but often the artwork is just leagues above what we get in the US. Seems like its changing for the newer systems but in the past its quite obvious...
7.) Sega CDX: this small all in-in-one beauty is the best. it takes up no space, looks cool, and plays both cd and carts. If only I could get it modded to play megacds!!
8.) NEC Hucards: definitely a dope looking media. even collecting loose carts is satisfying because you can store them in the plastic baseball card pages and keep them in a binder
AV Famicom + Disk System, Original Super Famicom + Satellaview, black N64 + 64DD, Panasonic Qube + Gameboy Player, CDX, White Saturn, White DC, Turbo Duo RX
those are my opinions anyway...feel free to add