I was wondering what you need to physically access quite often on the pc that you would need a door for?
I've got the door for a few reasons. My cab's downstairs in the living room, and all other PCs are upstairs. I don't have a wireless network, so any time I want to transfer files or use remote desktop, I've gotta run a 100 ft cable from the router to the cab, so in general I try to avoid doing it.
Also, the cab weighs a ton, is on carpet and sitting in a corner, and has a couch on the other side. It's no small task to move it away from the wall enough to get to the back and have enough room to access anything inside.
Lastly, I'm sure I'll be going into the cabinet less later, but as it is, my cab's a work in progress. I'm always getting in there for some thing or another (and forsee doing so for quite a while, I just don't have the time or money to just power through and get it done in a month or two).