Here is a starter checklist for you.
Security - have card key access or security puch code on all computer room doors. Restrict number of keys for doors. Deny access to all non-computer room personnel except when escorted. It is best to log all computer room traffic. No food or drink in computer room.
Power - Uninterruptible Power Supply to handle all servers and all major network equipment (WAN connections, switches, hubs, etc.). Maximize use of switches to minimize number of monitors (power hogs!). We ususally have 4-8 servers per monitor and the UPS is rated based on the load. Consider a generator that automatically ties into the UPS if you regularly have extended power outages. Get two good clocks. Hook one to UPS and one to regular power. They should always stay in synch unless you lose power.
Environmental monitoring and alert system - Consider a monitoring device that ties to a phone line (analog!) and calls your number when power goes out. These devices can monitor other environmental factors like temperature and humidity and call you when they go outside the parameters that you set. The more $$$ ones allow you to dial in and check environmental factors from a selection menu.
Fire protection - Sprinklers in the computer room? I don't think so! Think about fire extinguishers, emergency exits & signs, emergency lighting and non-water based fire supressants. The next time the power goes out have someone assigned to walk around and see if theemergency equipment is really working.
Remote Access - set up some secure method so you can dial into your computer room to check on the servers from a remote location. RAS (remote access server) and pcAnywhere are a couple of options.
Disaster Recovery/Business Continuity - develop a plan to be able to relocate your computer room should a long-term disaster occur. Also, develop a plan to be able to continue business o