The 800x600 resolution's final demise on the desktop will be accelerated by Windows 8 requiring a minimum resolution of 1024x768 for Metro applications to run.
Microsoft said on its Windows 8 blog that 98.8 percent of its Windows 7 users can run 1024x768 resolution or higher.
The stats back up this claim, as StatCounter shows that the 1024x768 is the most popular resolution in use today.
The Redmond giant went further and said that a resolution of 1366x768 is needed to support all of Windows 8's features. This resolution can fit a snapped application of 320px horizontally plus have another application open at 1024x768.
Machines running Windows 8 and having a resolution lower than 1024x768 will work but only support running desktop (non-Metro) applications.
This Metro restriction gives insight to the form factor of tablets that will run Windows 8 --- 7 inchers need not apply. Windows tablets are going to be on the larger end of the spectrum.
On the desktop I am thankful for this move. Hopefully, it can convince web designers that they can safely move beyond columns for content that are wider than 600 to 900 pixels and that they can use CSS media queries make their sites fit, or my preferred option which is to have websites fluid in design.
Most of the web is guilty of this practice and I do wish it would end.