U bet ur a$$ UR.
Set up meetings with all of your employees. The subject of the meeting should be something like, "Company Reorg." People who accept the meetings get to stay. People who decline them (because they "have work to do") should be canned immediately.
The "Thousand Rumors" Method
Spread rumors for ten or twelve months that employees are going to be fired, but that you've hired consultants to tell you exactly how to go about it. Eventually, you won't be able to stop the attrition--and you won't even have to do anything! Make sure they clean out their cubes.
Randomize Your Management
Fire half your managers and promote the other half. Allow no discernible policy to govern which managers get the axe--firings and promotions should befall a mix of incompetents and brilliant managers. Be sure that at least one manager who gets promoted has a history of HR violations. Again, attrition will work for you. Bonus: up-and-coming managers with fresh new ideas leave first.