Headless

In the good old days, most Unix boxes needed to have a keyboard, video and mouse plugged in or they got most upset. One solution is to use KVM over IP from the likes of Avocent. You plug a dongle into the back of the server and use the network to access the box remotely.

Another option is to go headless (needs some config changes) by enabling ssh, VNC, etc then disconnecting the monitor, keyboard and mouse. Power up a second computer on the same network, start the ssh client and log on to the headless server. You will find little difference between working from the console and the remote access connection. I only mention this as it a term a lot of IT people 
never come across. In the Windows world there is something called "Server Core" installation and I think that is the closest you can get to a headless server. If anyone with a Windows background would like to enlighten us please feel free.

One thing I would advise is to fit your racks with switched rack power distribution Units (PDUs) to provide advanced load monitoring combined with remote on/off switching control of individual outlets for power cycling, delayed power sequencing, and outlet use management. At least then 
you can try the switch it back off and back on again approach (handy on Sunday mornings or 3am call outs) but be aware this is last resort, always shutdown gracefully if you can.