If you have old servers in your office, please consider virtualization.
You will be taking your server and putting it in new hardware, there are many obvious benefits to this, not the least of which is a performance gain that is immediately noticeable.
Along with performance you can count on lowering your electric bill because not only are you now running less overall hardware, but the hardware is newer and more efficient.
Flexibility should also be included in the main list of advantages. Virtual servers are more flexible when it comes to backups, as well as adding hardware (like Memory, CPU and more disk space).