Ubuntu's new user interface Unity might not be perfect but the new eye candy it has brought to desktop has attracted many users. Only within a week of release of Ubuntu 11.04, complete Unity conversion packs for Windows have already been made.
The work is done by hameddanger who have made similar installers for Windows in the past. So, if you dual boot and want some consistency when you switch to Windows, these conversion packs may be useful.
Before downloading and running installers, please create System Restore Points so that you can fall back to your previous settings if you don't like it.
Ubuntu Skin Pack 3.0 for Windows XP
Ubuntu Skin Pack 4.0 for Windows 7
For more info visit hameddanger @ DeviantART