Firefox Developers: Read Jef Raskin's The Humane Interface

Why? Because it will explain why it's better to have the "close tab" button where you had it in version 1.5 rather than giving each tab it's own close button as you've done in 2.0.

Very aggravating, not only if you've grown used to where it is. I've seen commentary where some people are saying the old way was a bad design decision ("You can't tell which tab it's for!" - please, it's obvious it's for the tab you're viewing). One even claims that there could be a timing issue with opening and closing tabs. Poppycock, says I. Most of the people who claim this is "better" are people who seem to be using other methods to close tabs (like Ctrl-W), so they don't really get it. Granted, keystrokes are quicker than mouse actions, but if your hand is already on the mouse...

Fortunately, this comment here describes an easy way to go back to the old way (i.e.; the right way).

On the other hand, they've made it easier to manage your search engines in the search bar. You actually have an interface to remove items you don't want, like the majority of what Firefox gives you by default (in my case). Of course, until I found out about the keyboard options for the search bar (Ctrl-K plus Ctrl-Up/Ctrl-Down). I never used it.

(Yes, I recognize I'm complaining about a feature I always use the mouse for and talking about a feature that I ignored until I learned about a keyboard shortcut; it's not irony, it's the way I use the application. Deal.)