re: Tech closet?

Each room in my house has a cat6 run to a central location in the attic. In the attic I have a gigabit switch that has sufficient ports for all of the rooms.

In my office I have a set of shelves that is effectively my "tech closet." On these shelves I have my modem, router, a switch for all of my office equipment, a NAS with 4TB (4x1TB) in RAID5 for important data, a Mac server with 6TB additional storage (used for wireless Time Machine backups, torrent downloading, less important storage, etc.), and my work laptop, which needs to be used for certain applications, but instead of using the actual laptop I just stick it on the shelf and work from my personal computer at my desk and remote desktop into the laptop on the shelf if I need to use such an application.

An actual closet for this would be pretty cool, though. If you go that route, I can't stress enough how important ventilation is. With all of that stuff in my office, it's much, much warmer than the rest of the house. In a closet, it would certainly cause failures. Also make sure that if you want to put a router in the closet that it is in a good central location, or that you run cat6 to a good central location for a separate access point somewhere.