Here are the most beautiful Automotive Windows 7 Themes, including cars, bikes, motorcycles, planes.
1. Ducati 2 Theme
This free Windows 7 theme is for those who appreciate fine motorcycles.

Download From: Microsoft
2. Lamborghini Aventador LP700-4
The Themepack contains 13 wallpapers and a red window color scheme.

Download From: windows-7-themes.com.
3. Ferrari theme

Low-slung for killer downforce and decked out with stunning details like Testarossa-styled driver’s-side mirrors, this squadron of late-model Ferraris—including the F430 and the 458 Italia—will bring some serious swagger to your Windows 7 desktop.
Download From: Microsoft
4. BMW 5-series

This is a very nice theme with the 2010 BMW 5-series in the spotlight. I’ve used gentle colors so it won’t annoy you in a very long time. I hope you’ll enjoy it.
Download From: windows7themes.net
5. Akrapovic theme

Get close with the gleaming perfection of motorcycle exhaust components from the mind of Slovenian racer Igor Akrapovic. Used by high performance bikes around the world, and free for the gawking with this Windows 7 theme.
Download From: Microsoft
6. Porcsche

Bursting with both action shots and detailed views of distinctive design details, this free theme for Windows 7 is for fans of Porsche street and racing models.
Download From: Microsoft
7. Formula Truck

Download From: Windows7themes.net
8. Ford Lightning Hotrod

Download From: windows-7-themes.com
9. FIGHTERS

Download From: windows-7-themes.com
10. Infiniti

This swoon-worthy specialty racing car from Infiniti is seen from every angle in a free Windows 7 theme. Don’t miss the view from above that shows how the windshield swoops upward to become the roof of the vehicle.
Download From: Microsoft
11. Fighter Planes

Wallpaper SlideShow with 37 Wallpapers of Fighter Planes.
Download From: windows-7-themes.com