One of the best add-ons Rated 5 out of 5 stars
Absolutely brilliant addon and I commend the author! I hope development continues for FF 3.6 and eventually 4 when the developer needs to cater for a vastly changed themes. Perhaps you'll want to color just the top of tabs and fade down when FF becomes 'Chrome-like'.
Also, I think the default option should be set to the colours based on the domain-name, as this makes a lot more sense and allows the feature to be exploited by more users.