Vista themes are like skin on your default Vista. These themes will make Vista look amazing by providing different icons or wallpapers and yeah the sound and graphics effect.Windows Vista is growing everyday and becoming popular among 3d Fanatics. Directx10 , the secret of Vista has been boon to both game players and user experience on desktops. If you haven’t optimized Vista read Optimized and tweaked Vista Tips
I found these amazing themes which all vista users can use on their desktops. You can choose whichever suits your taste. Some of the themes might require Free Theme Manager. Click on the images and it will take you to download page.
Note : Please Backup Your Vista Before you install these themes. That’s for your safety. The author is not responsible for a third party tools.
Windows 7 Style for Vista
Glass Theme / Transparent Theme for Windows Vista
Alpha OS Suite
You can also try to Download Free Windows XP themes and styles if you are a xp user.In order to give your Windows XP a Vista-style look, you can either download the free themes or use Vista Transformation Pack.