Six tips for Firefox 2 - reinstate the Firefox 1.5 close tab button
There has been some discussion on the web lately on how Mozilla for the Firefox 2 codestream has removed the close button at the end of the tab script. It appears you can keep the Firefox 1.5 behaviour by modify a property on the about:config page. Another cool feature I learned from these tips is that you can undo the closing of a tab - nice!!
For more information see Six tips for Firefox 2 over at ZDNet.