Microsoft just announced Windows 10, skipping Windows 9.
SAN FRANCISCO (AP) - The next version of Microsoft's flagship operating system will be called Windows 10, as the company skips version 9 to emphasize advances it is making toward a world centered around mobile devices and Internet services.
Wouldn’t it be funny if instead of Windows 10, it was Win X. The ad battles between Apple and Microsoft would be so much more entertaining. Win X vs. OS X. BTW, the apple guys always say “OS Ten” not “OS X”.
OS X, whose X is the Roman numeral for 10 and is a prominent part of its brand identity, is built on technologies developed at NeXT between the second half of the 1980s and Apple's purchase of the company in late 1996. The 'X' is also used to emphasize the relatedness between OS X and UNIX.
Check out this comparison between Windows 7 vs. Macs.