Firefox Addons/Extensions I Can't Live Without

I have been using Firefox for a  couple of years now. Through the years i have added and deleted addons/extension that at first are useful then i have to left go because A.) i found a better extension B.) no longer useful to me and C.) the developer no longer update the said extension. So now i'm listing my Firefox extension i have been using for quite some time now.

1. DownThemAll! - The first and only download manager/accelerator built inside Firefox!
DownThemAll is all you can desire from a download manager: it features an advanced accelerator that increases speed up to 400% and it allows you to pause and resume downloads at any time.

DownThemAll is fast, reliable and easy-to-use! It lets you download all the links or images contained in a webpage and much more: you can refine your downloads by fully customizable criteria to get only what you really want![addons.mozilla.org/en-US/firefox/addon/201]

2. ScribeFire Next - A reboot of the full featured blog editor that integrates with your browser and lets you easily post to your blog.
This is a redesign of ScribeFire, one of the most popular add-ons for Firefox. ScribeFire is a full-featured blog editor that integrates with your browser and lets you easily post to all of your blogs.

You can post to blogs from Wordpress, Blogger, TypePad, Windows Live Spaces, Tumblr, Posterous, Xanga, LiveJournal, or any other blog that supports the MetaWeblog or MovableType APIs.[addons.mozilla.org/en-US/firefox/addon/199790]

3. Xmarks Sync - Xmarks is the #1 bookmarking add-on.
It takes only a moment to get up and running with Xmarks. After you install the add-on, click on the notification to set up Xmarks and start backing up and synchronizing your bookmarks. Install Xmarks on each computer you use, and it seamlessly integrates with your web browser and keeps your bookmarks safely backed up and in sync.

Xmarks works seamlessly across browsers. Today we support Firefox, Internet Explorer, Safari (MacOS only), and Google Chrome. Please visit our website at xmarks.com for more details.[addons.mozilla.org/en-US/firefox/addon/2410]

4. Live HTTP Headers - View HTTP headers of a page and while browsing.
[addons.mozilla.org/en-US/firefox/addon/3829]

5.  WebMail Notifier - WebMail Notifier checks your webmail accounts and notifies the number of unread emails.
WebMail Notifier checks your webmail accounts and notifies the number of unread emails...
Supports : gmail, yahoo, hotmail, aol, daum, naver, nate, paran, POP3/IMAP and more. [addons.mozilla.org/en-US/firefox/addon/4490]