Mac OS X theme for Ubuntu 11.10 – cool GTK3 theme.
Top 10 Gnome Shell Themes!
Mac OS X Theme for Ubuntu 11.04 – Natty Narwhal, make your Ubuntu Desktop look like Mac!
Finally here is my all time favorite – Awesome,great and best – collection of 10 cool Ubuntu Themes
..Actually, it is very simple to develop a windows 7 theme for Ubuntu but it’s not an easy task to develop a Ubuntu Theme for Windows 7 users(which will give the windows 7 users a feel/look of Ubuntu..