Windows 7 looks awesome but if you still need new themes for your Windows 7 installation then Microsoft has released 4 new themes for that. New themes are based on Christmas, Animals and Summit. Out of 4 new themes, 1 is on Cats, 1 is on Dogs, 1 is on Christmas and the 4’th theme is on Summit. All 4 themes are really good in quality and the integration as they are released by none other than Microsoft.
Each Themepack file is of ~10 MB in size. Download he files and double click on them to apply them on your desktop. Once the new theme will be applied on your desktop, It will appear under the “Personalization” option under Control Panel.
For other themes released by Microsoft for Windows 7, Checkout this official release page.