This add-on is a side-bar that displays tweets related to the page that you are visiting. You can choose the number of tweets to be displayed and how often the bar gets updated. Quite a useful add-on I must say, since it tells you exactly what the tweeteratti are saying about the content that you are reading. (Link)

This is one of my favorite add-ons that zooms the thumbnails of images on sites like Facebook, Twitter, MySpace, Amazon, Flickr, YouTube etc. You don't need to click on the image and visit a new page to see the original size of the image, all you need to do is hover the mouse over the image and it will zoom it for you. Trust me, it saves a whole lot of time. (Link)

There are many bloggers and site owners who miss out on including a 'share this' widget on their blog (like the button on the top right of this post). This add-on is a button that will be displayed near the address bar of your browser, with endless options of websites that you can share the content you are reading. (Link)

We all know how addictive and serendipitous StumbleUpon can get, so why not make things easier and get an easy button near the address bar, along with like and dislike buttons. I strongly recommend this add-on especially for bloggers who are continuously looking for information and interesting stuff online. (Link)

There's nothing very great about this add-on, but sure is pretty convenient. It adds a Facebook search button near your address bar from where you can search for your friends from any page that you are visiting. It also notifies you of friend requests, messages or pokes. A pop-up appears whenever your friends update their status. (Link)

It is a wonderful add-on that makes things so much easier when you are looking to convert some content into PDF; it does it directly from your browser. The only limitation with this add-on is that it does not convert HTML files and also not the files that are protected and a login is required (email letter will not be converted). (Link)

Again an easy solution for dictionary and translation where all you need to do is point or double click the word for its dictionary meaning, or select the whole page for translation. On double-clicking the word, it will display a pop-up with the meaning in it, it can also take you to the full definition of the word(s) through the 'more' link in the pop-up. Ever since I've installed this add-on, I can't seem to do without it. (Link)

I am aware of the fact that many site owners or bloggers despise add-ons that block the ads that they work so hard on and spend money on. But there are times, when you just wanna read and have control over the page that you are visiting and this add-on does just that for you by removing those banners and adverts. You can also customize filters if you like. (Link)

As the name of this add-on suggests, it helps you save the content that you wish to read later. You can read in offline mode and sync it with your smartphone or tablet. You can even share your 'read it later' list with your friends. (Link)

Bottom Error Console: 

Quite a useful add-on for developers, that splits the window and displays error console on the down side. "You can toggle the presence of the display with the status bar button or the shortcut key (Ctrl+Shift+B)" explains the developer of this add-on. (Link)

This add-on can be used to inspect and edit the DOM of any web document or XUL application. It inspects the structure and properties of a window and its content. Makes things pretty convenient for developers that you navigate through two-paned window displaying different views on documents and nodes in it. (Link)

As a developer this is one add-on that can make things work like a charm for you. It integrates with your browser to add easily accessible wealth management tools while you browse. You can edit, debug and monitor CSS, HTML and JavaScript in any web page. (Link)

So this sums up our entire list of best add-ons that you can have for Firefox. If you know of some more, then do share them with us and our readers in the comment section below.

34 Handpicked Firefox Add-ons/Extensions. Part 1.