Once addons were popular I tried a few and I loved them, so I packed my Firefox chock full of them, which gave me load of functionality, but resulted in slower loading times, more frequent crashes and general slowness and clutery.

Since then I have decided that the minimalistic approach is best. I can visit Twittwer’s home page if I want to add a tweet, I can visit Gmail to see if I have unread messages, right now I only have the most essential stuff on. I feel more productive this way actually since I can focus much more on the page I am viewing (working on), as opposed to the eye candy/masses of functionality at my fingertips. Are you the person who enjoys a minimalistic Firefox, or someone who needs to have all the latest addons right now? Let us know!

iGoogleBar ads the favicons of many Google services like Gmail, Google Calendar, Reader, even Documents, Notebook and Web Albums. What makes it really cool though is that you can access features from the bar, via a drop down menu. Clicking the calendar will yield a list of event and things to do, found in your calendar.

The unread emails and unread Reader items count is especially useful, you now only need to visit these services when you know there’s something to see. Yes, there are other ways to navigate easily other productive plugins and desktop applications that can show you unread mail for example, but this is unobtrusive, replaces something less useful, so even if you use it only now and again it may be worth the download.

With the level of dedication put forward by the Thunderbird developers and users it will definitely be the right move. In the meantime, here are 45+ valuable extensions for Thunderbird users that extend the functionality, add missing features and provide security enhancements.

Appearance:

Contacts Sidebar – displays the address book in the sidebar when toggled with F4.

Cute Menus – adds icons to all Thunderbird menu entries.

Flatstyle – changes the look and feel to resemble Microsoft Office.

Minimize to tray – moves Thunderbird from the task bar into the system tray.

Tiny Menu – save space by compacting the menu.

Composing:

Auto Zip Attachments – zips attachments automatically before sending the mail.

Clippings – Save frequently used texts to prevent typing the same texts over and over again.

Copy Plain Text – Copies texts without formatting.

Nested Quote Remover – removes nested quotes automatically when replying.

Signature Switch – switch signatures with ease.

Fun:

Bork Bork Bork – Feeoo veb peges oor meeel es spukee by zee Svedeesh Cheff.

Leet Key – 7r4n5f0rm5 0r 3n(0d35 53|3(73d 73×7 1n70 |337 5p34k 4nd d1ff3r3n7 3n(ryp710n5.

Smilie Inserter – insert smilies in messages.

Functionality

Addressbooks Synchronizer – synchronized selected address books with local, ftp, imap or webdav books.

Display Quota – displays IMAP quota and warns when a limit is reached.

Fox Clocks – keep an eye on the time around the world.

Lightning – finally a calendar for Thundebird.

Locale Switcher – lets you switch the locale setting with ease.

Quick Note – write down quick notes (phone numbers for instance)

Provider for Google Calendar – sync data between Lightning / Sunbird and Google Calendar.

Remove Duplicate Messages – scans for and removes duplicated messages.

TB Properties – adds a Properties function to display more information about images and links.

Thunderbrowse – allows you to view websites in Thunderbird instead of your default web client.

[UN]Read – adds a button and shortcut that switches between view all / view unread mode quickly.

Update Notifier – notifies the user whenever an update for an extension or theme is available.

Reading:

Change – currency converter for 36 currencies.

Dictionary Search – lookup a selected word.

GDirections – Uses Google and Yahoo maps to find directions from one of several locations that you have addded to the location of the selected text.

Image Zoom – adds the ability to zoom into images.

Maximize Message Pane – Collapses thread pane to maximize the message pane.

Quick Folders – bookmark mail folders for faster access.

Quote Colors – assigns colors to quotes depending on the quote level.

Open Long Url – makes it possible to open multi-line urls.

Text Size Toolbar – adds buttons to the toolbar which can increase and decrease text size.

Track Packages – track packages from various services such as UPS, Fedex and DHL with a right-click.

Security:

Enigmail – adds flexible and easy to install OpenPGP functionality to Thunderbird.

Sender Verification Extension – reports if the sender in the From header was the actual sender of the email when possible.

Thunder Plunger – removes traces of accounts that have been deleted in Thunderbird.

Xpunge – Compacts mail folders which gets rid of already deleted emails that are still stored in those folders unless compacted.

The major difference is how they add the functionality. Widgets for Opera usually open in their own window (like a mini sized popup) and one can opt to have the widget always on top. This means that they stay on top even if Opera is minimized. I actually prefer to browse the Opera website for Widgets because it looks much cleaner and professional than the one for Firefox. Not a fan of the windows marketplace at all. All widgets are free to download which is another similarity that Opera and Firefox share. Enough of the babbling, here is the list of 10 must-see Opera Widgets.

1. Video Downloader – lets you download videos from many video sites including youtube. It is a little bit different from the Firefox extension with the same name. This Video downloader opens a small popup and requires you to paste a link of the video into it. It displays the download link afterwards.
2. Gmail Checker – displays a very small icon with the amount of mails currently unread in your inbox. Can be moved around any way you like.
3. Image Grep – nice widget that makes it possible to search flickr, google and yahoo for tags and keywords specified. Displays the results neatly in its windows. F5 refreshes the results, a double-click loads the image in Opera.
4. Mini Del.icio.us – this one is fantastic. It ask for a del.icio.us username at first start and offers a quick and easy way to load any bookmark of that user.
5. gCalendar – read only Calendar that pulls data from Google Calendar. Great for the quick overview.
6. Bug Me Not  – Users submit general passwords to the Bug me not database and everyone else may use those passwords to visit the website and read content that is for members only. Just enter a url and the widget searches the bug me not database and displays the results.
7. Pandora Radio – displays the Pandora radio in the widget window. Easy and fast access to your radio stations.
8. Digg Frontpage – displays the frontpage news of digg.com
9. Fark Frontpage – similar widget that displays news of fark.com
10. Bittorent – searches many torrent search engines, displays result in the widget.

Each category has some subcategories that finally contain the links to the add-ons. Many of the add-ons listed are not free, you should enable the freeware only option if you would like to view only freeware add-ons. As an example, the privacy subcategory of security has 39 entries, if you choose only freeware add-ons the list is reduced to 14.

Microsoft introduced a rating system and comments system for their add-ons website, make sure you read the comments before you install an add-on.

There are of course not that many add-ons available at the moment, the list surely grows with time. I dislike the fact that freeware and commercial products are in that list, would love a similar system to the mozilla system with only freeware add-ons listed.

It is still a nice idea to take a look at the add-ons and install and test some of them.. I stick with firefox nevertheless.