Handhelds, Saturn, Sega CD, Sega Master System, PS1 and PS2:




Genesis, Dreamcast & more Saturn:



Most of the Saturn jewel case games are reproductions (my word for "burned CD with replica artwork"). I have a modchip in my Saturn to play CD-R's.
NES:

Found this display at a thrift store. Don't know what it was made for, but NES carts in sleeves fit perfectly. Contra cart is in my NES.
More NES & SNES:

N64 & Gamecube:

Consoles currently connected to my CRT TV:

Atari & portable games:

Console "bullpen":

I can rotate the Nintendo systems in and out pretty easily since they all use the same s-video cable (except the NES of course). NES, SMS & TG-16 all use the composite input on the front of the TV.
Modern games (mine & my son's):

My space is limited as my den doubles as my son's toy room, so this is about the extent of what I can display. I have boxes of loose accessories, Atari & Genesis carts, as well as several boxed systems such as Dreamcast, Genesis & ColecoVision. My original Xbox & Xbox 360 are hooked up to my living room HDTV.