Something I've learned as an old IT guy is that employee comfort is very under-rated. How comfortable an employee is with their work space is critical to productivity. I'm talking everything from the chair they sit in to what's on their monitor. If they're comfortable with windows and office and become uncomfortable with gmail and open office then you'll just kill productivity and whatever money you saved will be meaningless.
But people are always more comfortable with what they know. If that means that you never change anything, then where does that leave you in the long term ? Ultimately you need to make strategic long term choices with IT environments, and keeping yourself with old comfortable stuff isn't always the right solution, irrespective of any short term productivity losses.
A man is not complete until he is married -- then he is finished.