Google launches Chrome gallery
Google is out with a new Themes Gallery site for Chrome users - but not all Chrome users.
The new Themes Gallery currently is only for dev and beta channel users running Chrome 3.x. So for stable Windows users, you're out of luck.
For Linux and Mac users, there is no stable version, only the dev version, so you are in luck.
In comparison, Mozilla now has 20,000 different Personas (basically themes) available for Firefox users - so yeah Mozilla has a bit of a lead there. But hey you gotta start somewhere.