If you do NOT want to install Windows by any means (meaning no parallels/fusion, and no boot camp) then your only two options are Wine, and Crossover. Technically, crossover uses Wine, but it is a self contained package program that installs everything for you and makes the application good to go from the start.
I will say, however, that I have had literally ZERO success using Crossover. Most of the programs that it "supports" are through Steam, which doesnt help you if you have the disks of the game.
The only way I have ever had a reliable way of playing whatever game I wanted was through either Boot Camp or Parallels Desktop (with an installed copy of Win7). Parallels have worked hard to bring graphics enhancements to virtual desktops, and is my personal favorite program to use.
If you dont mind sitting down for 20 hours troubleshooting why the hell your program doesnt work, then Wine will (eventually) work for you! Otherwise, just install Windows. It is truly the easiest and best way to go.