I have relocated various aspects of my company 3 times. This included complete data center moves.
Don't underestimate the importance of planning, planning, planning. Generally, moves of this nature provide a very small window for execution, so the plan must be well thought out. Always make sure that there is a contingency plan in case of failure at any point in the process.
The key to a successful move is to do as much up front work as possible. Presumably you will have to move orinstall new data communication lines, phone lines, etc. These should all be installed beforehand and thoroughly tested. Don't cancel the old lines until the move is complete.
Next, make sure the site is prepped for the equipment. Make surethat you know where everything is going to go - a detailed floor plan. Make sure that all electrical outlets and cabling are in place and tested to support the equipment or users.
Have a prioritized list. You need to know exactly what is critical and what is not critical. Ensure that all critical servers and users are installed and tested first.
Plan for plenty of manpower because there is usually lots of activities and extra hands are always welcome.
Also, alert any vendors that play a critical part in your systems. Make sure that they know about the moves and are "on call", if necessary to support you.
Once again, make sure that your contingency plan is as tight as your primary plan.
Good luck. This type of project is challenging and rewarding.