Yeah, I agree. Most companies still using Windows XP are going to move to Windows 7.
I work for a University, and while we do buy and test every version of Windows that comes out, usually it is rare for us to migrate the entire campus to a every new version of Windows that comes out.
We obviously used Win XP forever, but we skipped over Vista due to compatibility and stability concerns.
At the moment we are nearly done with our Windows 7 deployment, but it looks like we are going to be skipping over Windows 8. Windows 8 is different enough from previous version of Windows that we will have to offer a wide range of training classes. And we don't want to pay to create and run these training classes in the mists of budget cuts.
Side note, but we've bought and migrated all of our Mac users on campus to every new version of Mac OS X that has been released since 10.4. The operating system changes so little between each version, the cost is so low, and compatibility has never been a concern. Though I will say Apple's switch from PPC to Intel 7-8 years ago caused great havoc.