Rated 4 out of 5 stars
This is a very nice extension. It doesn't work right on Fx where I use TabbedBrowsingExtensions 3 but that extension is not available for SeaMonkey and Colorful Tabs works great on SeaMonkey. I wish it worked with TBE on Fx too. This makes the tabs pretty to look at and easy to tell at a glance which is which if you have a bunch of tabs open.
The latest version (at the author's website) works just fine with SeaMonkey 2.10 so don't be put off by the message here at Addons that this extension is incompatible with the current version of SeaMonkey.