Windows Vista’s default theme is quite good and is a great improvement over Windows XP. Here is a small collection of all time top Vista AERO themes for Windows Vista. Full credit goes to the authors of respective themes. I have given the download link as author’s page, from where you can download the theme. Let us know any other themes you like!
Read how to install third-party Vista themes here
Aero Diamond Theme
Aero 4074 Theme
Vista Breeze Theme