Oh yeah its Pixel Vision.
Download free on: http://pulseh.deviantart.com/art/Pixe...
Installing
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1. Copy the 'PixelVision' folder to Steam's "skins" directory.
2. Install the fonts included in the 'Fonts' folder to C:\Windows\Fonts\.
3. Non-English Users: open the file called 'locale.ini' found in the 'PixelVision' folder that you
just extracted and follow the instructions provided within.
4. In Steam, go the Interface tab in Settings, and select PixelVision from the third drop-down box, and make sure that "Enable DirectWrite for improved font smoothing and kerning" is ticked.
5. Restart, enjoy, and don't forget to take a look at the new Tweaks!