I really like Windows 7, but despite it being the best Windows version to date, it shouldn't come as a surprise that it's still far from perfect.
So, let the rant begin.

• Backups created using the built-in backup utility can't be restored onto hard disks that are smaller than the source disk, even if the data would fit just fine. Feeling safe already? Like PCWorld's Lincoln Spectre put it:

  Microsoft has a history of bundling really bad backup programs with their operating systems. The company has been accused of a lot of monopolistic behavior, but their backup programs often seemed designed to not threaten the market for third-party competitors.

• Windows Explorer sucks in many ways, but not being able to to display folder sizes is probably one of the most sucky features. Apple has had this feature since I started using computers in the early nineties. Go figure.
• Windows Explorer
• Windows 7 does not support RAW images out of the box. You have to install a driver from the manufacturer. If you're a smart-ass 64 bit Windows 7 user with a Canon camera, then you basically can go fuck yourself and spent another $20 on a 3rd party utility. I won't mention the fact that this is also perfectly possible on Macs).
• Windows 7 telnet client does not have any key to cancel a connection. It used to be Ctrl-], but this does not work. If the connect does not work, you'll have to wait for it to time-out. Same for Windows Server 2012.