You are using Gmail and you find it a little gloomy, you would like to give it a little more color and gaiety, or match it with your iGoogle ?
 
Well, since the beginning of the year, Google added many themes in order to customize iGoogle  (with themes realized by artists from the world...) and also suggest you to create your own theme.

Read the whole article

Great. So are there any themes for Google search?

I like  https://addons.mozilla.org/en-US/firefox/addon/8434/ and https://addons.mozilla.org/en-US/firefox/addon/6076
I use the later one now, as the host of the first one is sometimes down..
 
(remember to enable the "Google Redesigned" theme from Preferences if you go with Better GMail)

 
Um... iGoogle?..