I just switched to the latest dev build of Google Chrome, and it supports multiple themes, in an easy-to-install .crx format. So I thought I’d go ahead and make my gray theme (since I can’t stand the default bright blue). Another benefit is finally being able to skin the bookmark bar.
If you want to switch to dev build from stable OR beta, just grab the chrome changer file and switch to dev, then close and restart Chrome. Then click the wrench then click About Google Chrome. Then get the latest version. You can now install crx themes.
Here’s the theme file:
Simply Gray

(Edit 8/4/2009: For the dev build version of the theme, get my updated version)
This is random, but I just got the latest stable version of Chrome, and all the skins that are floating around the internet do not seem to work with the latest version. So I made a new one. It just replaces that bright blue with gray. For some reason, that blue top has always bothered me. Anyway, here’s what it looks like:

Here’s the file:
default.dll
To change the theme for Google Chrome you will need to replace the default.dll file with the new theme file. Location for theme folder are as follows:
For Vista Users:
C:\Users\UserName\AppData\Local\Google\Chrome\Application\0.2.172.33\Themes\
For XP Users:
C:\Documents and Settings\UserName\Local Settings\Application Data\Google\Chrome\Application\0.2.172.33\Themes\
Replace the number with your version of Google Chrome.
Make sure to keep a backup of the default.dll, before you overwrite it with a new one.