To the left is my current shelving setup...
All cartridge games are in universal game cases with printed inserts, several of which are custom.
The PS1 games have all had their jewel cases stored away and have been placed in much more durable DVD cases. This also makes browsing PS1 games much easier. I was never able to read the spines on the original cases. I need to fix the spine on the Suikoden case, but I'm particularly fond of the Final Fantasy collection, and the Tomb Raider collection, even though I kind of hate the games!
The SNES games are all in custom cases, and some of the games have custom labels. I opted to get reproductions of my FF games, as now I can have FF4 at its proper difficulty and better translation, a SNES version of FF5, and the uncensored and better translated version of FF6.
Super Metroid and Mega Man X are both SFC versions that I placed in NTSC shells with the custom labels. My SNES is modded to play SFC carts, but I wanted the custom shells

The Genesis cases are all completely custom, as my OCD simply would not allow the mismatched stock cases! I still go back and forth, as they take a lot of time to make and I hate wasting the original clamshells... I may revisit them in the future once I start collecting for the Genesis in a month or so.
GBA/GBC/GB games are all stored in custom DS sized cases fitted to hold all three cartridge sizes. Inserts are original box art when available.
The consoles...
1-Chip SNES and Model 2 Genesis. I prefer the Model 2 because I don't want to have to deal with a wonky cable just to get stereo sound. I have a Model 1 in the garage if I feel so inclined. Also, space is a premium.
Super Slim PS2 on top, then an N64, then the RGB modded NES.
Wii U with GC adapter up top, then Super Slim PS3, then an OG Xbox. The Xbox wont be long for this setup, as my brother just donated me his 360. If the backwards compatibility works well enough, it will replace it.
The Gamecube with GBA Player, and the Dreamcast...
Finally, the Xbox One.
More importantly, below that you'll see my Hama SCART switch on the left for the SNES, Genesis and NES, and to the right is my XRGB Framemeister, which is what allows me to hook everything up to my 50" HDTV without any input latency and with a crystal clear picture.
Proof!
And that's it for now. I'd like to get some decorations going on the walls and eventually I'll be adding more shelves. I already have a growing stack of games that need plastic homes...