I built this "closet" off my gym, so my bike wouldn't be smack dab in the middle of the room, allowing my wife to be able to use the gym and her aerobic/step videos without having to deal with my crap.
Friends say they would go crazy in that small room, however, it's like a little sanctuary for me. I have a white board on the wall to write down any thoughts, the DVD player in the back feeds a full size TV in the main gym, I have complete control of music, movies, lighting, fan speed all from my saddle, I can place plenty of water bottles on the shelving behind... I'm about to sell my home and I really think I'm going to miss my gym....