With the introduction of Windows 8, Microsoft may have reduced the number of retail SKUs, but there are still many options compared with the single OS X installation. Selecting the correct version for running in Boot Camp or other virtualization solution is important.
John Rizzo at MacWindows says that the wrong version of Microsoft Windows 8 may not install in Apple's Boot Camp or in Parallels Desktop or VMware Fusion solutions. Or the version may be more software (and cost) than you need.
Windows 8 Upgrade will not work if you're creating a brand new installation of Windows 8 in Boot Camp, or are creating new virtual machine with Parallels Desktop, VMWare Fusion, or Oracle VirtualBox. For these situations, you need a Windows 8 System Builder OEM version. The term "System Builder" refers to people who build their own PC from parts. Creating a new virtual machine or a Boot Camp partition is the equivalent of building your own system.
Check out the full MacWindows article for pricing, feature and compatibility issues.
Rizzo also raises another excellent point: there's no reason not to keep your previous virtual machines installed (except I would add for disk space on a machine with solid-state disks). This is an easy way to make sure of compatibility when transitioning your workflow. As Rizzo says, "having multiple OS's installed at the same time is one advantage of virtual machines over Boot Camp."
Speaking of virtualization, Codeweavers earlier in the month released an update to CrossOver 12 for both Mac and Linux versions. Version 12.2 improves Quicken stability as well as CrossOver's "Mac Driver" integration technology that was introduced in Version 12. It allows CrossOver to work without the X Window System required with previous versions.
On the Mac OS, we have continued to improve our new Mac Driver technology. This release includes support for drag and drop in the Mac Driver, as well as changes which should improve the visual experience and reduce window flicker. The Mac Driver is maturing rapidly and will be the default option in our next major release. All experienced CrossOver users are invited to turn it on and see how it works.