"It just slows things down the more protocols you have installed"
True, but on a small home LAN you would never see a realworld performance hit. On the other hand, if you are sharing files on that LAN, binding file sharing to NetBEUI instead of TCP/IP can be a legitimate security benefit. Don't get me wrong, I only use IP myself, but I would not be worried about protocol overhead on a LAN with less than 10 nodes, especially NetBEUI, which has very little overhead to begin with.